When were the North American time zones established?
Standard time
In 1870 Charles F. Dowd proposed four time zones based on the meridian through Washington, DC for North American railroads. In 1872 he revised his proposal to base it on the Greenwich meridian. Sandford Fleming, a Scottish-born engineer operating in Canada, proposed worldwide Standard Time at a meeting of the Royal Canadian Institute on February 8, 1879. Cleveland Abbe advocated standard time to better coordinate international weather observations and resultant weather forecasts, which had been coordinated using local solar time. In 1879 he recommended four time zones across the contiguous United States, based upon Greenwich Mean Time. The General Time Convention (renamed the American Railway Association in 1891), an organization of US railroads charged with coordinating schedules and operating standards, became increasingly concerned that if the US government adopted a standard time scheme it would be disadvantageous to its member railroads. William F. Allen, the Convention secretary, argued that North American railroads should adopt a five-zone standard, similar to the one in use today, to avoid government action. On October 11, 1883, the heads of the major railroads met in Chicago at the Grand Pacific Hotel and agreed to adopt Allen's proposed system.
Chamorro Time Zone
The Chamorro Time Zone, formerly the Guam Time Zone, is a United States time zone which observes standard time ten hours ahead of Coordinated Universal Time (). The clock time in this zone is based on the mean solar time of the 150th meridian east of the Greenwich Observatory.
Universal Time
Apart from the Nepal Time Zone (UTC+05:45), the Chatham Standard Time Zone (UTC+12:45) used in New Zealand's Chatham Islands and the officially unsanctioned Central Western Time Zone (UTC+8:45) used in Eucla, Western Australia and surrounding areas, all timezones in use are defined by an offset from UTC that is a multiple of half an hour, and in most cases a multiple of an hour.
Time in Australia
The colonies enacted time zone legislation, which took effect in February 1895. The clocks were set ahead of GMT by 8 hours in Western Australia; by 9 hours in South Australia (and the Northern Territory, which it governed); and by 10 hours in Queensland, New South Wales, Victoria, and Tasmania. The three time zones became known as "Western Standard Time", "Central Standard Time", and "Eastern Standard Time". Broken Hill in the far west of New South Wales also adopted Central Standard Time due to it being connected by rail to Adelaide but not Sydney at the time.
Time in the United States
Weather service chief Cleveland Abbe had needed to introduce four standard time zones for his weather stations, an idea which he offered to the railroads. Operators of the new railroad lines needed a new time plan that would offer a uniform train schedule for departures and arrivals. Four standard time zones for the continental United States were introduced at noon on November 18, 1883, when the telegraph lines transmitted time signals to all major cities.
Time in Nunavut
When the territory was created in 1999, the new government believed a unified time zone would make it easier for its citizens to conduct business. Public hearings noted there was support for this idea, although disagreement as to which time zone to observe. The territorial government announced that effective October 31, 1999 all clocks would change to Central Standard Time. Iqaluit, the capital located in the far eastern edge of the Eastern time zone, was unhappy with this decision. The city council voted against the measure and vowed to keep the city on Eastern time. As late October 1999 approached the city council backed down and agreed to accept the change to Central time "in the spirit of working with the Nunavut government". They agreed to review the decision in six months.
Alaska Time Zone
The Standard Time Act of 1918 authorized the Interstate Commerce Commission to define each time zone. The United States Standard Alaska Time was designated as UTC−10. Some references prior to 1967 refer to this zone as Central Alaska Standard Time (CAT) or as Alaska Standard Time (AST). In 1966, the Uniform Time Act renamed the UTC−10 zone to Alaska-Hawaii Standard Time (AHST), effective April 1, 1967. This zone was renamed in 1983 to Hawaii-Aleutian Standard Time when the majority of Alaska was moved out of the zone.
Time zone
Offsets from UTC are written in the format ±[hh]:[mm], ±[hh] [mm], or ±[hh] (either hours ahead or behind UTC). For example, if the time being described is one hour ahead of UTC (such as the time in Berlin during the winter), the zone designator would be "", "+0100", or simply "+01". This numeric representation of time zones is appended to local times in the same way that alphabetic time zone abbreviations (or "Z", as above) are appended. The offset from UTC changes with daylight saving time, e.g. a time offset in Chicago, which is in the North American Central Time Zone, is "" for the winter (Central Standard Time) and "" for the summer (Central Daylight Time).
International Meridian Conference
In the United States, the problems were much more severe, with one table showing over 100 local times varying by more than 3 hours. In 1870, Charles F. Dowd published a pamphlet titled "A System of national time and its application" advocating three time zones across the country based on the Washington meridian, modifying this to four zones based on the Greenwich meridian in 1872.
Nautical time
These nautical letters have been added to some time zone maps, like the World Time Zone Map published by Her Majesty's Nautical Almanac Office (NAO), which extended the letters by adding an asterisk (*), a dagger (†) or a dot (•) for areas that do not use a nautical time zone (areas that have a half-hour or quarter-hour offset, and areas that have an offset greater than 12 hours), and a section sign (§) for areas that do not have a legal standard time (the Greenland ice sheet and Antarctica). The United Kingdom specifies UTC−3 for the claimed British Antarctic Territory.
Time in Maine
The entirety of Maine currently uses the Eastern Time Zone, which is UTC-5. Daylight saving time is used; during that period, Maine uses UTC-4. The eastern portion of Maine which is east of 67.5° W geographically is in the Atlantic Time Zone, which is used by adjacent New Brunswick. Eastern Maine has the earliest solar noon of the entire contiguous United States; solar noon can be as early as 11:35 and 11:11am in West Quoddy Head.
Eastern Time Zone
Most cable television and national broadcast networks advertise airing times in Eastern time. National broadcast networks (ABC, CBS, The CW, FOX, NBC) generally have two primary feeds, an eastern feed for Eastern and Central time zones, and a tape-delayed western feed for the Pacific Time Zone. The prime time is set on Eastern and Pacific at 8:00 p.m., with the Central time zone stations receiving the eastern feed at 7:00 p.m. local time. Mountain Time Zone stations receive a separate feed at 7:00 p.m. local time. As Arizona does not observe daylight saving time, during the summer months, it has its own feed at 7:00 p.m. local time. Cable channels with a separate western feed (such as HBO, whose western feed is called "HBOW") generally air the same programming as the eastern feed delayed by three hours. Other cable networks such as the Discovery family of networks repeat their prime time programming three hours later; this allows for the same show to be advertised as airing at "8:00 p.m. E/P" (that is, "8:00 p.m. Eastern and Pacific time"). Networks specializing in the airing of sports events, such as ESPN, advertise all of their programming in Eastern and Pacific, incorporating the 3-hour time difference (as in "8:00 p.m. Eastern/5:00 p.m. Pacific") and leaving viewers in the remaining time zones to calculate start time in their own areas.The Bahamas officially observe both Eastern Standard Time during the winter months and Eastern Daylight Time during the summer months. Cuba generally follows the U.S. with Eastern Standard Time in the winter, and Eastern Daylight Time in the summer, but the exact day of change varies year to year. Cayman Islands and Jamaica use Eastern Standard Time year-round.
Prime time
In North America, television networks feed their prime time programming in two blocks: one for the Eastern and Central time zones, and the other, on a three-hour tape delay, for the Pacific time zone, to their local network affiliates. In Atlantic Canada (including Newfoundland) as well as Alaska and Hawaii, there is no change in the interpretation or usage of “prime time” as the concept is not attached to time zones in any way. Affiliates in the Mountain, Alaskan, and Hawaiian zones are either on their own to delay broadcast by an hour or two, or collectively form a small, regional network feed with others in the same time zone.
Time in the United States
The United States uses nine standard time zones. As defined by US law they are:
Coordinated Universal Time
The time zone using UTC is sometimes denoted or by the letter "Z"—a reference to the equivalent nautical time zone (GMT), which has been denoted by a "Z" since about 1950. Time zones were identified by successive letters of the alphabet and the Greenwich time zone was marked by a "Z" as it was the point of origin. The letter also refers to the "zone description" of zero hours, which has been used since 1920 (see time zone history). Since the NATO phonetic alphabet word for "Z" is "Zulu", UTC is sometimes known as "Zulu time". This is especially true in aviation, where "Zulu" is the universal standard. This ensures that all pilots, regardless of location, are using the same 24-hour clock, thus avoiding confusion when flying between time zones. See the list of military time zones for letters used in addition to "Z" in qualifying time zones other than Greenwich.
Daylight saving time in the Americas
DST (UTC−3) is generally observed from the first Sunday of September to the third Sunday of April. However, the Falklands remained on DST throughout 2011 and 2012.
History of time in the United States
Time zone boundaries have changed greatly since their original introduction and changes still occasionally occur. DOT issues press releases when these changes are made. Generally, time zone boundaries have tended to shift westward. Places on the eastern edge of a time zone can effectively move sunset an hour later (by the clock) by shifting to the time zone immediately to their east.
Time in Chile
Chile returned to for winter time for 3 months starting in 2016. Between 2016 and 2018, this began on the second Saturday of May and ended on the second Saturday of August; from 2019 onward, it will begin on the first Saturday of April and end on the first Saturday of September.
Since 2017 a new time zone in the Magallanes and Chilean Antarctica region has been implemented, giving two different times in Continental Chile for the first time.
The winter time starts the first Saturday of April and ends on the first Saturday of September.
It has 2 hours of difference from the Continental time and changes the same days.
The official time on the mainland is now in the Magallanes and Chilean Antarctica Region is , and on Easter Island is .
Effects of time zones on North American broadcasting
With four time zones in the contiguous United States, American broadcast television networks generally broadcast at least two separate feeds to their owned-and-operated stations and affiliates, as do cable/satellite channels: the "eastern feed" that is aired simultaneously in the Eastern and Central Time Zones, and the "western feed" that is tape-delayed three hours for those in the Pacific Time Zone. This ensures that a program, for example, that airs at 8:00 p.m. EST on the East Coast is also shown locally at 8:00 p.m. on the West Coast. Networks may also broadcast a third feed specifically for the Mountain Time Zone, on which programs are usually broadcast on a one-hour delay from the Eastern Time Zone. Otherwise, some stations in the Mountain Time Zone use the western feed, while others get a mix of both the Eastern and Pacific feeds.
Daylight saving time in the United States
From 1945 to 1966 there was no federal law on daylight saving time, so localities could choose when it began and ended or drop it entirely. As of 1954, only California and Nevada had statewide DST west of the Mississippi, and only a few cities between Nevada and St. Louis. In the 1964 Official Railway Guide, 21 of the 48 contiguous states had no DST anywhere.
Time zone
Timekeeping on the American railroads in the mid-19th century was somewhat confused. Each railroad used its own standard time, usually based on the local time of its headquarters or most important terminus, and the railroad's train schedules were published using its own time. Some junctions served by several railroads had a clock for each railroad, each showing a different time.
Charles F. Dowd proposed a system of one-hour standard time zones for American railroads about 1863, although he published nothing on the matter at that time and did not consult railroad officials until 1869. In 1870 he proposed four ideal time zones (having north–south borders), the first centered on Washington, D.C., but by 1872 the first was centered on the meridian 75° W of Greenwich, with geographic borders (for example, sections of the Appalachian Mountains). Dowd's system was never accepted by American railroads. Instead, U.S. and Canadian railroads implemented a version proposed by William F. Allen, the editor of the "Traveler's Official Railway Guide". The borders of its time zones ran through railroad stations, often in major cities. For example, the border between its Eastern and Central time zones ran through Detroit, Buffalo, Pittsburgh, Atlanta, and Charleston. It was inaugurated on Sunday, , also called "The Day of Two Noons", when each railroad station clock was reset as standard-time noon was reached within each time zone. The zones were named Intercolonial, Eastern, Central, Mountain, and Pacific. Within a year 85% of all cities with populations over 10,000, about 200 cities, were using standard time. A notable exception was Detroit (which is about halfway between the meridians of eastern time and central time) which kept local time until 1900, then tried Central Standard Time, local mean time, and Eastern Standard Time before a May 1915 ordinance settled on EST and was ratified by popular vote in August 1916. The confusion of times came to an end when Standard zone time was formally adopted by the U.S. Congress in the Standard Time Act of March 19, 1918.
Naming of the Americas
The earliest known use of the name "America" dates to April 25, 1507, where it was applied to what is now known as South America. It appears on a small globe map with twelve time zones, together with the largest wall map made to date, both created by the German cartographer Martin Waldseemüller in Saint-Dié-des-Vosges in France. These were the first maps to show the Americas as a land mass separate from Asia. An accompanying book, "Cosmographiae Introductio", anonymous but apparently written by Waldseemüller's collaborator Matthias Ringmann, states, "I do not see what right any one would have to object to calling this part [that is, the South American mainland], after Americus who discovered it and who is a man of intelligence, Amerigen, that is, the Land of Americus, or America: since both Europa and Asia got their names from women".
Time zone
The first adoption of a standard time was on December 1, 1847, in Great Britain by railway companies using GMT kept by portable chronometers. The first of these companies to adopt standard time was the Great Western Railway (GWR) in November 1840. This quickly became known as Railway Time. About , time signals were first transmitted by telegraph from the Royal Observatory, Greenwich. Even though 98% of Great Britain's public clocks were using GMT by 1855, it was not made Britain's legal time until . Some British clocks from this period have two minute hands—one for the local time, one for GMT.
Uniform Time Act
The most noteworthy exceptions are the states of Arizona and Hawaii, the commonwealths of the Northern Mariana Islands and Puerto Rico, and the territories of American Samoa, Guam, and U.S. Virgin Islands, none of which observe Daylight Saving Time. The various Native American nations within Arizona have the right to use or not use DST. The Navajo Nation has chosen to use DST throughout its territory, which includes parts of New Mexico and Utah. In contrast, the Hopi Nation, whose territory is surrounded entirely by the Arizona portion of the Navajo Nation, has chosen not to use DST.
History of time in the United States
If the original proposal to extend DST through the last Sunday in November had been adopted, the entire United States, with the exception of the states that exempted themselves, would have experienced the latest sunrises of the year during the month of November, which would have approached the extremely late sunrise times when DST went into effect on January 6, 1974 due to the 1973 energy crisis creeping after 9 am in places like New Salem, North Dakota at the northwestern edges of time zones.
Alaska Time Zone
The Alaska Time Zone applies to the territory of the state of Alaska east of 169°30′ W. Given that the UTC−09:00 time corresponds to the solar time at 9 × 15° = 135° W (roughly, Juneau), the westernmost locales of the Alaska Time Zone are off by up to 169°30′ − 135° = 34°30′ from local solar time. This means that when a clock correctly set to Alaska time, at a location just east of 169°30′ W, shows noon, local solar time is around 9:42 a.m. When UTC−08:00 is applied in the summer (because of daylight saving time), this effect becomes even more apparent. For example, on June 12 at noon AKDT, the solar time at the extreme westerly points of the Alaskan time zone will be only 8:42 a.m. Very few people notice this, however, as these locations are virtually uninhabited, and for the very few people who do live there, the long days in the summer and short days in the winter make the sunrise and sunset times less important than areas closer to the equator. By contrast, in Juneau, which is much closer to the 135° west meridian, mean solar noon occurs around 11:57 a.m., very close to clock noon.
Time in Canada
Canada is divided into six time zones, based on proposals by Scottish Canadian railway engineer Sir Sandford Fleming, who pioneered the use of the 24-hour clock, the world's time zone system, and a standard prime meridian. Most of Canada operates on standard time from the first Sunday in November to the second Sunday in March and daylight saving time the rest of the year.
Time in Alaska
From 1901 until 1983 there were the following timezones:
Effects of time zones on North American broadcasting
Local programming such as locally produced newscasts are not typically affected as many stations air their morning newscast at 4:00, 4:30, 5:00 or 5:30 a.m., and their early evening newscasts at 5:00 and/or 6:00 p.m.; however, the late evening newscast is affected due to the differences in time between time zones, meaning that if the late local news starts at 10:00 p.m. Central time on one network station, an affiliate of the same network in the Eastern Time Zone airs its newscast at 11:00 p.m.; network evening newscasts on CBS, ABC, and NBC are affected since they are usually scheduled to air at 6:30 p.m. Eastern Time (barring preemption due to network sports coverage or at the discretion of the local station, breaking news or severe weather coverage) in order to sync up with its simultaneous broadcast in the Central Time Zone. Midday newscasts are not necessarily affected, depending on whether the station's affiliated network schedules their daytime lineup simultaneously in the Eastern and Central Time Zones (as with ABC and CBS) or just to the Eastern Time Zone first (as with NBC). The late night program lineups on ABC, CBS, NBC and Fox are also similarly timeshifted, airing a half-hour later (after a newscast or syndicated programming if the station does not run news programming) but are shifted due to the time zone differences (a bigger issue with first-run late night programs that air after 12:30 a.m. Eastern Time since the later start time may subject these programs to a potentially decreased audience). Many Fox, CW and MyNetworkTV affiliates, and some independent stations carry a prime time newscast that is similarly affected by the timeshifting of the prime time schedule, meaning that if said late evening newscast starts at 9:00 p.m. Mountain Time on one network station, an affiliate of the same network in the Pacific time zone would air its news at 10:00 p.m.
Surface weather analysis
The weather data was at first less useful as a result of the different times at which weather observations were made. The first attempts at time standardization took hold in Great Britain by 1855. The entire United States did not finally come under the influence of time zones until 1905, when Detroit finally established standard time. Other countries followed the lead of the United States in taking simultaneous weather observations, starting in 1873. Other countries then began preparing surface analyses. The use of frontal zones on weather maps did not appear until the introduction of the Norwegian cyclone model in the late 1910s, despite Loomis' earlier attempt at a similar notion in 1841. Since the leading edge of air mass changes bore resemblance to the military fronts of World War I, the term "front" came into use to represent these lines.
North American Numbering Plan
The new numbering plan was officially accepted in October 1947, dividing most of North America into eighty-six numbering plan areas (NPAs). Each NPA was assigned a numbering plan area code, often abbreviated as "area code". These codes were first used by long-distance operators to establish long-distance calls between toll offices. The first customer-dialed direct call using area codes was made on November 10, 1951, from Englewood, New Jersey, to Alameda, California. Direct distance dialing (DDD) was subsequently introduced across the country. By the early 1960s, most areas of the Bell System had been converted and DDD had become commonplace in cities and most larger towns.
Coordinated Universal Time
In 1955, the caesium atomic clock was invented. This provided a form of timekeeping that was both more stable and more convenient than astronomical observations. In 1956, the U.S. National Bureau of Standards and U.S. Naval Observatory started to develop atomic frequency time scales; by 1959, these time scales were used in generating the WWV time signals, named for the shortwave radio station that broadcasts them. In 1960, the U.S. Naval Observatory, the Royal Greenwich Observatory, and the UK National Physical Laboratory coordinated their radio broadcasts so that time steps and frequency changes were coordinated, and the resulting time scale was informally referred to as "Coordinated Universal Time".
Eastern Time Zone
Five states are partly in the Eastern Time Zone, with the remaining portions in the Central Time Zone. They are:
Eastern Time is also used somewhat as a "de facto" official time for all of the United States because it includes the capital city (Washington D.C.), the most populous city (New York City), and half of the country's population. For this reason, media organizations will often report when events happened or are scheduled to happen in Eastern Time even if they occurred in another time zone, and TV schedules are also almost always posted in Eastern Time. In the United States, all nationally televised morning programs (except "Good Morning America Weekend Edition" which some ABC affiliates on the east coast air on a tape-delay), some daytime talk shows, evening newscasts, most talent and awards shows, and any other nationally televised event that airs live on American television during prime time and on the weekends (such as sports television) are broadcast live in the Eastern Time Zone. Major professional sports leagues also post all game times in Eastern time, even if both teams are from the same time zone, outside of Eastern Time. For example, a game time between two teams from Pacific Time Zone will still be posted in Eastern time (for example, one may see "Seattle at Los Angeles" with "10:00 p.m." posted as the start time for the game, often without even clarifying the time is posted in Eastern time).
Central Time Zone
In those areas of the Canadian and American time zones that observe DST, beginning in 2007, the local time changes at 02:00 local standard time to 03:00 local daylight time on the second Sunday in March and returns at 02:00 local daylight time to 01:00 local standard time on the first Sunday in November. Mexico decided not to go along with this change and observes their from the first Sunday in April to the last Sunday in October. In December 2009, the Mexican Congress allowed ten border cities, eight of which are in states that observe Central Time, to adopt the U.S. daylight time schedule effective in 2010.
Time in Indiana
Time zones were first adopted by the United States Congress with the Standard Time Act of 1918. All of Indiana was located in the Central Time Zone. It was at this time the dividing line between Eastern Time and Central Time was moved from the Pennsylvania-Ohio state line to the Indiana–Ohio state line. Daylight saving time (DST) was included in the original Standard Time Act. A year later, Congress repealed daylight saving time from the Standard Time Act of 1918, though some communities continued to follow it. During World War II, daylight saving time was once again mandated by Congress to conserve energy. After the war, the mandate to observe daylight saving time was lifted again.
Time in Namibia
From 1994 until 2017 Namibia used Winter time, the practice of setting clocks back during winter months by one hour. In this period Namibian Standard Time was at Central Africa Time in summer, and (West Africa Time) in winter. Winter time began on the first Sunday in April at 03:00, and lasted until the first Sunday in September, 02:00 hours. In the Zambezi Region in the far north-east of Namibia clocks were not changed and remained on Central Africa Time all year round so that during winter time, Namibia spanned two time zones. The Namibian Standard Time was thus UTC+02:00 (derived from South African Standard Time) in summer, and (equivalent to West Africa Time) in winter.
North American Aerospace Defense Command
The North American Air Defense Command was recommended by the Joint Canadian–U.S. Military Group in late 1956, approved by the U.S. Joint Chiefs of Staff in February 1957, and announced on 1 August 1957. NORAD's command headquarters was established on 12 September 1957 at Ent Air Force Base's 1954 blockhouse. In 1958, Canada and the United States agreed that the NORAD commander would always be a United States officer, with a Canadian vice commander, and Canada "agreed the command's primary purpose would be…early warning and defense for SAC's retaliatory forces." In late 1958, Canada and the United States started the Continental Air Defense Integration North (CADIN) for the Semi-Automatic Ground Environment air defense network. The initial CADIN cost sharing agreement between the two countries was signed off on 5 January 1959. Two December 1958 plans submitted by NORAD had "average yearly expenditure of around five and one half billions", including "cost of the accelerated Nike Zeus program" and three Ballistic Missile Early Warning System (BMEWS) sites.
Canada's NORAD bunker at CFB North Bay with a SAGE AN/FSQ-7 Combat Direction Central computer was constructed from 1959 to 1963, and each of the USAF's eight smaller AN/FSQ-8 Combat Control Central systems provided NORAD with data and could command the entire United States air defense. The RCAF's 1950 "ground observer system, the Long Range Air Raid Warning System", was discontinued and on 31 January 1959, the United States Ground Observer Corps was deactivated. The Cheyenne Mountain nuclear bunker's planned mission was expanded in August 1960 to "a hardened center from which CINCNORAD would supervise and direct operations "against space attack" as well as air attack" The Secretary of Defense assigned on 7 October 1960, "operational command of all space surveillance to Continental Air Defense Command (CONAD) and operational control to North American Air Defense Command (NORAD)".
Bill Sheffield
While governor, Sheffield pushed an unpopular bill through the state legislature to consolidate Alaska's time zones. Prior to the passage of this bill, Alaska was spread over four time zones (Pacific, Yukon, Alaska-Hawaii, and Bering). Sheffield's bill placed virtually the entire state (with the sole exception of the Aleutians, starting just west of Dutch Harbor) into the Yukon Time Zone (which was then renamed the Alaska Time Zone). Initially, this was poorly received; those in the panhandle lost their sense of unity with the west coast of the United States, and those in the heartland of the state were placed, in effect, in a perpetual daylight saving time. More than twenty years later, the state legislature was still debating the issue, with some members wanting to return the panhandle and capital to Seattle time, and with others claiming that Sheffield broke his promise to revisit the change after a one-year trial period.
Atlantic Time Zone
No portion of the continental United States currently uses Atlantic Time, although it is used by the territories of Puerto Rico and the U.S. Virgin Islands. A number of New England states are considering a regional change to Atlantic Standard Time year-round (with no observance of daylight saving time), even though only a small portion of Maine lies to the east of the 67.5°W theoretical extent of this zone. Florida is in the process of enacting a similar change; in both cases any changes will need to be approved by the United States Department of Transportation and the United States Congress.A Massachusetts commission concluded in 2017 that the benefits of changing to Atlantic Standard Time year-round would outweigh the disadvantages, provided that a majority of northeastern states made the same change. In May 2017, the Maine Senate approved a change to AST, on the condition that there would be a referendum, and that Massachusetts and New Hampshire decided to make the same switch. Also in 2017, the New Hampshire House of Representatives approved a bill in favour of a regional change, but this was voted down by the state's Senate. Similar bills have been put forward in Connecticut and Rhode Island.
2015–16 North American winter
The 2015–16 North American winter refers to winter in North America as it occurred across the continent from late 2015 through early 2016. While there is no well-agreed-upon date used to indicate the start of winter in the Northern Hemisphere, there are two definitions of winter which may be used. Based on the astronomical definition, winter begins at the winter solstice, which in 2015 occurred late on December 21, and ends at the March equinox, which in 2016 occurred on March 20. Based on the meteorological definition, the first day of winter is December 1 and the last day February 29. Both definitions involve a period of approximately three months, with some variability. Winter is often defined by meteorologists to be the three calendar months with the lowest average temperatures. Since both definitions span the calendar year, it is possible to have a winter storm in two different years.
History of time in the United States
The history of standard time in the United States began November 18, 1883, when United States and Canadian railroads instituted standard time in time zones. Before then, time of day was a local matter, and most cities and towns used some form of local solar time, maintained by some well-known clock (for example, on a church steeple or in a jeweler's window). The new standard time system was not immediately embraced by all.
Standard time
Standard time is the synchronization of clocks within a geographical area or region to a single time standard, rather than using solar time or a locally chosen meridian (longitude) to establish a local mean time standard. Historically, the concept was established during the 19th century to aid weather forecasting and train travel. Applied globally in the 20th century, the geographical areas became extended around evenly spaced meridians into time zones which (usually) centered on them. The standard time set in each time zone has come to be defined in terms of offsets from Universal Time. In regions where daylight saving time is used, that time is defined by another offset, from the standard time in its applicable time zones.
Time in North Korea
On 29 April 2018, North Korean leader Kim Jong-un announced his country would be returning to to realign its clocks with South Korea. On 30 April 2018, the Supreme People’s Assembly of North Korea issued a decree about changing the time zone in North Korea as a further step in unifying Korea and eliminating differences between the South and North. The time zone change was applied at 23:30 on 4 May 2018 ().
Tz database
Rule US 1918 1919 - Mar lastSun 2:00 1:00 D
Rule US 1918 1919 - Oct lastSun 2:00 0 S
Rule US 1942 only - Feb 9 2:00 1:00 W # War
Rule US 1945 only - Aug 14 23:00u 1:00 P # Peace
Rule US 1945 only - Sep 30 2:00 0 S
Rule US 1967 2006 - Oct lastSun 2:00 0 S
Rule US 1967 1973 - Apr lastSun 2:00 1:00 D
Rule US 1974 only - Jan 6 2:00 1:00 D
Rule US 1975 only - Feb 23 2:00 1:00 D
Rule US 1976 1986 - Apr lastSun 2:00 1:00 D
Rule US 1987 2006 - Apr Sun>=1 2:00 1:00 D
Rule US 2007 max - Mar Sun>=8 2:00 1:00 D
Rule US 2007 max - Nov Sun>=1 2:00 0 S
Rule NYC 1920 only - Mar lastSun 2:00 1:00 D
Rule NYC 1920 only - Oct lastSun 2:00 0 S
Rule NYC 1921 1966 - Apr lastSun 2:00 1:00 D
Rule NYC 1921 1954 - Sep lastSun 2:00 0 S
Rule NYC 1955 1966 - Oct lastSun 2:00 0 S
Zone America/New_York -4:56:02 - LMT 1883 Nov 18 12:03:58
For each time zone that has multiple offsets (usually due to daylight saving time), the tz database records the exact moment of transition. The format can accommodate changes in the dates and times of transitions as well. Zones may have historical rule changes going back many decades (as shown in the example above).
Time in the United States
Time in the United States, by law, is divided into nine standard time zones covering the states and its possessions, with most of the United States observing daylight saving time (DST) for approximately the spring, summer, and fall months. The time zone boundaries and DST observance are regulated by the Department of Transportation. Official and highly precise timekeeping services (clocks) are provided by two federal agencies: the National Institute of Standards and Technology (NIST) (an agency of the Department of Commerce); and its military counterpart, the United States Naval Observatory (USNO). The clocks run by these services are kept synchronized with each other as well as with those of other international timekeeping organizations.
Charles F. Dowd
Except for meridians based on Greenwich, the system adopted by the railroad industry on 18 November 1883 ignored Dowd's proposal. The adopted system by William F. Allen, editor of the "Traveler's Official Railway Guide", had borders that passed through railway terminals, even some in major cities, like Detroit, Buffalo, Pittsburgh, Atlanta, and Charleston—these formed the border between the eastern and central time zones. It included a fifth time zone for eastern Canada, called Intercolonial Time after the Intercolonial Railway serving eastern Canada. Each of these boundary cities had to adopt one of the two railroad zones or continue to use local mean solar time. The 1918 Standard Time Act moved the borders to relatively rural areas.
Daylight saving time in the Americas
Since 2007, in areas of Canada and United States in which it is used, daylight saving time begins on the second Sunday of March and ends on the first Sunday of November. In Mexico, Congress has consistently been refusing to adopt this schedule on a nationwide basis for nearly a decade. Therefore, only certain border cities in Mexican states that observe DST follow the same pattern as Canada and the United States. The rest of Mexico remains out of phase beginning DST on the first Sunday of April and ending on the last Sunday of October, the same schedule followed by Canada and the United States prior to 2007.
Effects of time zones on North American broadcasting
The Eastern Time Zone is commonly used as a " de facto" official time for the United States because it includes the nation's capital city, Washington D.C.; the most populous city, New York City; and half of the country's population.
UTC−07:00
UTC−07:00 is a time offset that subtracts 7 hours from Coordinated Universal Time (UTC). 
In North America, it is observed in the Mountain Time Zone during standard time, and in the Pacific Time Zone during the other 8 months (see Daylight saving time). A few places use it year-round.
North American Datum
In 1901 the United States Coast and Geodetic Survey adopted a national horizontal datum called the United States Standard Datum, based on the Clarke Ellipsoid of 1866. It was fitted to data previously collected for regional datums, which by that time had begun to overlap. In 1913, Canada and Mexico adopted that datum, so it was also renamed the North American Datum.
Daylight saving time
The dates on which clocks are to be shifted also vary with location and year; consequently, the time differences between regions also vary throughout the year. For example, Central European Time is usually six hours ahead North American Eastern Time, except for a few weeks in March and October/November, while the United Kingdom and mainland Chile could be five hours apart during the northern summer, three hours during the southern summer, and four hours a few weeks per year. Since 1996, European Summer Time has been observed from the last Sunday in March to the last Sunday in October; previously the rules were not uniform across the European Union. Starting in 2007, most of the United States and Canada observe DST from the second Sunday in March to the first Sunday in November, almost two-thirds of the year. Moreover, the beginning and ending dates are roughly reversed between the northern and southern hemispheres because spring and autumn are displaced six months. For example, mainland Chile observes DST from the second Saturday in October to the second Saturday in March, with transitions at local time. In some countries time is governed by regional jurisdictions within the country so that some jurisdictions shift and others do not; this is currently the case in Australia, Brazil, Canada, Mexico, and the United States.
Quintana Roo
On February 1, 2015, Quintana Roo officially adopted a new time zone, Southeastern, which is five hours behind Coordinated Universal Time (). Quintana Roo does not observe daylight saving time, so Southeastern Time is constant throughout the year (that is, it does not shift forward in the spring and back in the fall). Southeastern Time (ST) is the same as Eastern Standard Time (EST) and Central Daylight Time (CDT). This means that in the winter, Quintana Roo has the same time as regions observing EST, such as the eastern U.S., eastern Canada, Cuba, and Jamaica; and in the summer, Quintana Roo has the same time as regions observing CDT, such as central Mexico.
Effects of time zones on North American broadcasting
The most common set of programming chosen by stations aligned with the Big Three television networks (ABC, CBS and NBC) is to air a local newscast at 5:00 p.m., national news at 5:30 p.m., another local newscast at 6:00 p.m. and syndicated programming at 6:30 p.m., though some Fox stations that maintain a newscast schedule comparable to stations tied to the Big Three (commonly stations that were former ABC, NBC and CBS affiliates themselves) carry a 60- or 90-minute block of news from 5:00 to 6:00 (or 6:30) p.m. with an additional half-hour of local news in the 5:30 p.m. timeslot as Fox does not air a national evening newscast; a few stations not affiliated with the Big Four networks, such as WGN-TV, KTLA in Los Angeles and WJXT in Jacksonville, Florida, follow a similar scheduling format with their early evening newscasts. Most Big Three affiliates in the Eastern and Pacific time zones follow this early evening newscast model as well, running a 90-minute block of news from 5:00 to 6:30 p.m., particularly if they run a network's national evening newscast at 6:30 p.m. Eastern and Pacific Time. Some stations, regardless of time zone, even show a newscast from 6:00 to 7:00 p.m., which if run on a network station in the Central or Mountain time zones would lead into primetime network programming. Some television stations (such as WKYC and WJW in Cleveland, Ohio, or WJAR in Providence, Rhode Island) have recently begun using the fact that primetime in the Eastern Time Zone begins at 8:00 p.m. to their advantage by carrying a newscast during the 7:00 p.m. hour, generally in order to attract viewers who work longer days and cannot return home to watch a 5:00 or 6:00 p.m. newscast.
WWVB
Each change in the DST bits will first be received in the mainland United States between 16:00 (PST) and 20:00 (EDT), depending on the local time zone and on whether DST is about to begin or end. A receiver in the Eastern time zone (UTC−5) must therefore correctly receive the "DST is changing" indication within a seven-hour period before DST begins, and six hours before DST ends, if it is to change the local time display at the correct time. Receivers in the Central, Mountain, and Pacific time zones have one, two, and three more hours of advance notice, respectively.
Sandford Fleming
After missing a train while traveling in Ireland in 1876 because a printed schedule listed p.m. instead of a.m., he proposed a single 24-hour clock for the entire world, with the 24 hour divisions (labelled A-Y, excluding J) arbitrarily linked to the Greenwich meridian, which was designated G. At a meeting of the Canadian Institute in Toronto on February 8, 1879, he linked it to the anti-meridian of Greenwich (now 180°). He suggested that standard time zones could be used locally, but they were subordinate to his single world time, which he called Cosmic Time. He continued to promote his system at major international conferences including the International Meridian Conference of 1884. That conference accepted a different version of Universal Time but refused to accept his zones, stating that they were a local issue outside its purview. Nevertheless, by 1929, all major countries in the world had accepted time zones.
Alaska Time Zone
With the reorganization of Alaska's time zones in 1983 to place the entire state in either a zone based on UTC−09:00 or UTC−10:00, the Yukon Time Zone based on UTC−09:00 was renamed the Alaska Time Zone.
National League East
The division was created when the National League (along with the American League) added two expansion teams and divided into two divisions, East and West effective for the 1969 season. The National League's geographical alignment was rather peculiar as its partitioning was really more north and south instead of east and west. Two teams in the Eastern Time Zone, the Atlanta Braves and the Cincinnati Reds, were in the same division as teams on the Pacific coast. This was due to the demands of the Chicago Cubs and St. Louis Cardinals, who refused to support expansion unless they were promised they would be kept together in the newly created East division.
History of time in the United States
From 1945 to 1966 U.S. federal law did not address DST. States and cities were free to observe DST or not, and most places that did observe DST did so from the last Sunday in April to the last Sunday in September. In the mid-1950s many areas in the northeastern United States began extending DST to the last Sunday in October. The lack of standardization led to a patchwork where some areas observed DST while adjacent areas did not, and it was not unheard of to have to reset a clock several times during a short trip (e.g., bus drivers operating on West Virginia Route 2 between Moundsville, West Virginia, and Steubenville, Ohio had to reset their watches seven times over 35 miles).
Daylight saving time in the Americas
Daylight saving time in the Americas is the arrangement in the Americas by which clocks are advanced by one hour in spring and moved back in autumn, to make the most of seasonal daylight. The practice is widespread in North America, with most of Canada, Mexico, and the United States participating, but much less so in South America.
Eastern Time Zone
The boundary between time zones is set forth in the Code of Federal Regulations, with the boundary between the Eastern and Central Time Zones being specifically detailed at 49 CFR 71.
North American Regional Broadcasting Agreement
The initial NARBA bandplan, also known as the "Havana Treaty", was signed by the United States, Canada, Mexico, Cuba, the Dominican Republic, and Haiti on December 13, 1937, and took effect March 29, 1941. A series of modifications and adjustments followed, also under the NARBA name. NARBA's provisions were largely supplanted in 1983, with the adoption of the Regional Agreement for the Medium Frequency Broadcasting Service in Region 2 (Rio Agreement), which covered the entire Western hemisphere. However, current AM band assignments in North America largely reflect the standards first established by the NARBA agreements.
Effects of time zones on North American broadcasting
Effectively, the East, Mountain and West network feeds allow prime time on broadcast television networks to end at 10:00 p.m. Central and Mountain and 11:00 p.m. Eastern and Pacific. When it first expanded its programming into prime time in April 1987, Fox became the first major broadcast network in the U.S. to offer a "common prime" schedule; this type of scheduling subtracts an hour from the prime time schedule, reducing it to two hours on Monday through Saturdays and three hours on Sundays – ending evening network programming earlier than NBC, CBS and ABC did – and continue to do (Fox did expand its Sunday primetime schedule into the 10:00 p.m. timeslot in September 1987, before giving back that hour to its stations in September 1993). The WB and UPN followed the "common prime" scheduling model when they both launched in January 1995; the replacements for those networks, The CW and the MyNetworkTV program service, similarly used that model upon their launches in September 2006.
Pacific Time Zone
The zone is two hours ahead of the Hawaii–Aleutian Time Zone, one hour ahead of the Alaska Time Zone, one hour behind the Mountain Time Zone, two hours behind the Central Time Zone, three hours behind the Eastern Time Zone, and four hours behind the Atlantic Time Zone.
UTC−06:00
UTC−06:00 is a time offset that subtracts six hours from Coordinated Universal Time (UTC). 
In North America, it is observed in the Central Time Zone during standard time, and in the Mountain Time Zone during the other eight months (see Daylight saving time). Several Latin American countries and a few other places use it year round.
Central Time Zone
The North American Central Time Zone (CT) is a time zone in parts of Canada, the United States, Mexico, Central America, some Caribbean Islands, and part of the Eastern Pacific Ocean.
Central Standard Time (CST) is behind Coordinated Universal Time (UTC). During summer most of the zone uses daylight saving time (DST), and changes to Central Daylight Time (CDT) which is behind UTC.
UTC+11:30
On November 2, 1868, New Zealand officially adopted a standard time to be observed nationally, and was perhaps the first country to do so. It was based on the longitude 172° 30' East of Greenwich, that is 11 hours 30 minutes ahead of Greenwich Mean Time. This standard was known as New Zealand Mean Time (NZMT). Today this would be around the same zone covered by UTC+11:30. New Zealand changed from NZMT to New Zealand Standard Time (NZST) as in 1946 (after using this timezone as a daylight saving time since 1928, including permanent daylight saving from 1941). It was officially changed to 12 hours in advance of UTC in 1946.
Time in Australia
Since 1899, the only major changes in Australian time zones have been the setting of clocks to one-half hour earlier than Eastern time (GMT plus 10:30) on the territory of Lord Howe Island, and Norfolk Island changing from to on 4 October 2015.
Time in the United States
In October 1884, the International Meridian Conference at Washington DC adopted a proposal which stated that the prime meridian for longitude and timekeeping should be one that passes through the centre of the transit instrument at the Greenwich Observatory in the United Kingdom (UK). The conference therefore established the Greenwich Meridian as the prime meridian and Greenwich Mean Time (GMT) as the world's time standard. The US time-zone system grew from this, in which all zones referred back to GMT on the prime meridian.
Time in New Zealand
In 1941, during the Second World War, clocks were advanced half an hour, making New Zealand 12 hours ahead of GMT. This change was made permanent from 1946 by the "Standard Time Act 1945", at which the time at the 180°E meridian was made the basis for New Zealand Time. NZST remained half an hour ahead of NZMT, and the Chatham Islands 45 minutes ahead of NZST.
In the late 1940s the atomic clock was developed and several laboratories began atomic time scales. A new time scale known as Coordinated Universal Time (UTC) was adopted internationally in 1972. This was based on the readings of atomic clocks, updated periodically in accordance with time variations in the Earth's rotation by the addition or deletion of seconds (called leap seconds). The "Time Act 1974" defines New Zealand Standard Time as 12 hours in advance of UTC.
Time in Norway
It was not until 1885 the first suggestions came to introduce standard time in Norway, but this met great opposition by influencing groups and locally in the districts of Norway. The most complicated of four propositions was to divide Norway into 5 time zones 15 minutes apart. But none of them was accepted. In 1893 the time issue emerged again, and since the last time, the neighbouring countries Sweden and Denmark had adopted standard time, so also Germany (Central European time). In Norway, the railways in western and eastern Norway would be connected in a few years, and now the proposition to adapt to Central European was widely accepted. Hence, one standard time was introduced January 1., 1895 and has since then remained Greenwich + 1 (Central European time). On this date church clocks was either moved backward (east of 15°E), or forward (west of 15°E), except for Hadsel and Steigen parishes that continued with their local time as their churches lie almost on the 15°E meridian. The local time continued to live on for quite some time, especially in rural communities, where both the local and standard time were in use (the latter being referred to as "railway time").
Coordinated Universal Time
The westernmost time zone uses , being twelve hours behind UTC; the easternmost time zone, uses , being fourteen hours ahead of UTC. In 1995, the island nation of Kiribati moved those of its atolls in the Line Islands from UTC−10 to so that Kiribati would all be on the same day.
Daylight saving time in the Americas
Brazil adopted DST (called "horário de verão"—"summer time"—in Portuguese) for the first time in 1931, and it was in effect across the entire country. The duration and regional applicability of DST has varied over the years (see for details). As of 2013, DST is used only in the southern region (the states of Rio Grande do Sul, Santa Catarina, Paraná), the southeast region (the states of São Paulo, Rio de Janeiro, Espirito Santo, Minas Gerais), and the central-west region (the state of Goiás and the Distrito Federal, and the states of Mato Grosso and Mato Grosso do Sul).
Tz database
These are rule lines for the standard United States daylight saving time rules, rule lines for the daylight saving time rules in effect in the US Eastern Time Zone (called "NYC" as New York City is the city representing that zone) in some years, and zone lines for the America/New_York time zone, as of release version "tzdata2011n" of the time zone database. The zone and rule lines reflect the history of DST in the United States.
Effects of time zones on North American broadcasting
Local stations and affiliates must schedule their local and syndicated programming around their respective network's feed. Because primetime programs on the East Coast feed are simulcast in two time zones, stations in the Central Time Zone are affected differently from those in the Eastern Time Zone. An hour of syndicated programming time (between 7:00 and 8:00 p.m. in the Eastern and Pacific time zones) is lost in the Central and Mountain time zones since network primetime in those areas starts at 7:00 p.m., forcing stations in Mountain or Central time (or in parts of both zones) to choose between airing their 6:00 p.m. newscast and another syndicated or locally produced program or airing shows in "blocks" preferred by syndicators (for example, "Wheel of Fortune" and "Jeopardy!" together or "Entertainment Tonight" and "The Insider" together).
Daylight saving time in the United States
By the Energy Policy Act of 2005, daylight saving time (DST) was extended in the United States beginning in 2007. As from that year, DST begins on the second Sunday of March and ends on the first Sunday of November. In years when April 1 falls on Monday through Wednesday, these changes result in a DST period that is five weeks longer; in all other years the DST period is instead four weeks longer. In 2008 daylight saving time ended at 2:00 a.m. DST (0200) (1:00 a.m. ST) on Sunday, November 2, and in 2009 it began at 2:00 a.m. (3:00 a.m. DST) on Sunday, March 8.
North American Numbering Plan expansion
The North American Numbering Plan was devised in the 1940s, implemented in 1947, and has provided customer direct-dialed long-distance telephone service since 1951. Occasionally, the growing demand for telephone numbers has mandated certain changes in the format of telephone numbers and method by which they are allocated to telephone companies. Instead of expanding the size of telephone numbers, as implemented in many countries outside North America, the NANP was designed as a closed numbering plan, having a fixed number of digits, three digits for the numbering plan area (NPA) code and seven digits for telephone numbers that are unique in each NPA. The telephone number was further distinguished as consisting of three digits that identified each central office and four digits for each subscriber station connected to the same central office. From 1947 to c. 1960, the initial two digits of the central office code were mapped to two letters of an often locally significant name, the central office name or exchange name. However, this scheme, practiced since its invention by W. G. Blauvelt of AT&T in 1917, prevented the use of numerous digit combinations that could only be associated with unpronounceable or, at best, confusable names. All-number calling removed these restrictions and permitted the phasing out of exchange names. Central office codes were initially still restricted from using digits "0" and "1" in the middle position, which provided a distinction to area codes, which always had "0" or "1" in the middle position. This last restriction was removed by 1995, with the phase-out of electromechanical switching systems by programmable electronic switching systems (ESS).
Western Conference (NHL)
The Northwest Division was dissolved in 2013. Its American teams joined the Central, while the Canadian teams returned to the Pacific. With this 2013 realignment, the Central Division is based almost entirely in the Central Time Zone (the only exception being the Colorado Avalanche, who are in the Mountain Time Zone), and the Pacific Division is based entirely within the Mountain and Pacific Time Zones.
Daylight saving time in the United States
By 1962, the transportation industry found the lack of consistency confusing enough to push for federal regulation. The result was the Uniform Time Act of 1966 (P.L. 89-387). Beginning in 1967, the act mandated standard time within the established time zones and provided for advanced time: clocks would be advanced one hour beginning at 2:00 a.m. on the last Sunday in April and turned back one hour at 2:00 a.m. on the last Sunday in October. States were allowed to exempt themselves from DST as long as the entire state did so. If a state chose to observe DST, the time changes were required to begin and end on the established dates. In 1967, Arizona and Michigan became the first states to exempt themselves from DST (Michigan would begin observing DST in 1972). In 1972, the act was amended (P.L. 92-267), allowing those states split between time zones to exempt either the entire state or that part of the state lying within a different time zone. The newly created Department of Transportation (DOT) was given power to enforce the law. , the following states and territories are not observing DST: Arizona, Hawaii, American Samoa, Puerto Rico, and the Virgin Islands.
Elgin National Watch Company Observatory
Prior to the creation of time zones, cities had substantial differences in the standards of time—in Wisconsin alone, over thirty-eight times were used at a given moment. In 1908, Theodore Roosevelt finally demanded that the United States Bureau of Standards encourage precise timing across the nation. In 1910, the Elgin National Watch Company decided to respond by building its own observatory so that the timing in its watches would be scientifically accurate. Dr. William W. Payne of the Goodsell Observatory was named the first director. Sidereal time was determined on Riefler Clock No. 220 by measuring the position of the stars in the night sky based on the position of the telescope (which could only move north-south along a meridian line). Eleven vertical wires were inside the telescope eyepiece. An astronomer would press a button every time a star appeared to cross one of the wires, which would send an impulse to the clock. This was compared with the solar time observed on the Riefler Clock No. 224 and results published by the "American Ephemeris and Nautical Almanac". The result was a clock that was accurate to the hundredth of a second. In the factory, the sounder audibly ticked off the seconds so that workers could set the watches accurately. After the opening of the observatory, the Elgin National Watch Company adopted the slogan: "Elgin Takes The Time From The Stars And Puts It In Your Pocket". The Illinois government also equipped the observatory with thermometers, a thermograph, barometer, barograph, rain gauge, and weather vane. This was intended to provide data on weather to Springfield, but was also reproduced in local newspapers. The company was watchful of humidity, as this could affect delicate processes.
Universal Time
Standard time, as originally proposed by Scottish-Canadian Sir Sandford Fleming in 1879, divided the world into twenty-four time zones, each one covering 15 degrees of longitude. All clocks within each zone would be set to the same time as the others, but differed by one hour from those in the neighboring zones. The local time at the Royal Observatory in Greenwich was announced as the recommended base reference for world time on 22 October 1884 at the end of the International Meridian Conference. This location was chosen because by 1884 two-thirds of all nautical charts and maps already used it as their prime meridian. The conference did not adopt Fleming's time zones because they were outside the purpose for which it was called, which was to choose a basis for universal time (as well as a prime meridian).
United States Virgin Islands
The U.S. Virgin Islands are located in the Atlantic Standard Time zone and do not participate in daylight saving time. When the mainland United States is on Standard Time, the U.S. Virgin Islands are one hour ahead of Eastern Standard Time. When the mainland United States is on daylight saving time, Eastern Daylight Time is the same as Atlantic Standard Time.
Day
For civil purposes, a common clock time is typically defined for an entire region based on the local mean solar time at a central meridian. Such "time zones" began to be adopted about the middle of the 19th century when railroads with regularly occurring schedules came into use, with most major countries having adopted them by 1929. As of 2015, throughout the world, 40 such zones are now in use: the central zone, from which all others are defined as offsets, is known as , which uses Coordinated Universal Time (UTC).
Mitch Daniels
One of the most controversial measures Daniels successfully pushed through was the state adoption of Daylight Saving Time, which Daniels argued would save the state money on energy costs. Although the state is in the Eastern Time Zone, Indiana's counties had adopted their own time zone practices, and in practice the state effectively observed two different times, and the central part of the state maintained a single time—Eastern Standard—year round. Interests for both EST and CST time zones had prevented the official adoption of daylight saving since the 1930s, and had led to decades of debate. Daniels pressed for the entire state to switch to Central Time, but the General Assembly could not come to terms. Ultimately after a long debate, they adopted Eastern Daylight Saving Time in April 2005, the measure passing by one vote, putting all but northwestern and southwestern Indiana on the same time for the first time.
Uniform Time Act
The Uniform Time Act of 1966, , was a Law of the United States to "promote the adoption and observance of uniform time within the standard time zones" prescribed by the Standard Time Act of 1918. Its intended effect was to simplify the official pattern of where and when daylight saving time (DST) is applied within the U.S. Prior to this law, each state worked out its own scheme for the dates of beginning and ending DST, and in some cases, which parts of the state should use it.
Daylight saving time in the United States
All U.S. insular territories with civilian government (American Samoa, Guam, Northern Mariana Islands, Puerto Rico, and the Virgin Islands) lie in the tropics and do not observe DST.
Daylight saving time
The history of time in the United States includes DST during both world wars, but no standardization of peacetime DST until 1966. In May 1965, for two weeks, St. Paul, Minnesota and Minneapolis, Minnesota were on different times, when the capital city decided to join most of the nation by starting Daylight Saving Time while Minneapolis opted to follow the later date set by state law. In the mid-1980s, Clorox (parent of Kingsford Charcoal) and 7-Eleven provided the primary funding for the Daylight Saving Time Coalition behind the 1987 extension to U.S. DST, and both Idaho senators voted for it based on the premise that during DST fast-food restaurants sell more French fries, which are made from Idaho potatoes.
Time in Mexico
The time zone "Hora del Sureste" (75° W) was created for tourist reasons in 1981, originally covering the states of Campeche, Yucatán, and Quintana Roo. The three states returned one year later to the "Hora del Centro" (90° W); Quintana Roo, however, returned to the "Hora del Sureste" (75° W) from October 1997 to August 1998 and then again in February 2015.
2016–17 North American winter
The 2016–17 North American winter refers to winter in North America as it occurred across the continent from late 2016 through early 2017. While there is no well-agreed-upon date used to indicate the start of winter in the Northern Hemisphere, there are two definitions of winter which may be used. Based on the astronomical definition, winter begins at the winter solstice, which in 2016 occurred on December 21, and ends at the March equinox, which in 2017 occurred on March 20. Based on the meteorological definition, the first day of winter is December 1 and the last day February 28. Both definitions involve a period of approximately three months, with some variability. Winter is often defined by meteorologists to be the three calendar months with the lowest average temperatures. Since both definitions span the calendar year, it is possible to have a winter storm in two different years.
Standard time
In the Netherlands, introduction of the railways made it desirable to create a standard time. On 1 May 1909, or Dutch Time was introduced. Before that, time was measured in different cities and in the east of the country, this was a few minutes later than in the west. In 1909, a national time was introduced which was the same as the local time in Amsterdam, to be precise the exact time of the Wester Tower (Westertoren/4°53'01.95" E). This time was indicated as GMT +0h 19m 32.13s until 17 March 1937, after which it was simplified to GMT+0h20m. This time zone was also known as the "Loenen time" or "Gorinchem time", as this was the exact time in both Loenen and Gorinchem. At noon in Amsterdam, it was 11:40 in London and 12:40 in Berlin.
International Date Line
The Russian Empire settled northwest North America from Siberia, from the west with its own Julian calendar (it did not adopt the Gregorian calendar until 1918). The United States purchased Russian America while based in the contiguous United States, from the east with its own Gregorian calendar (adopted in 1752 while several British colonies). The transfer ceremony occurred on the day that the commissioners appointed by the governments of Russia and the United States for that purpose arrived via the at New Archangel (Sitka), the capital of Russian America. The United States recorded this date as Friday, (Gregorian), now known as Alaska Day, whereas the Russian governor, who had remained in New Archangel, would have recorded it as Saturday, (Julian). Senator Charles Sumner stated during his three-hour ratification speech (an encyclopedic discussion of Russian America) on Tuesday, , that this day of the week and calendar discord should be changed. Because the transfer of ownership officially occurred at Sitka mean solar time (time zones were not yet in use), that was the date and time that Alaska changed from an Asian and Julian date to an American and Gregorian date. If the transfer had occurred at the preceding midnight then Friday, (Julian) would have been followed by Friday, (Gregorian), a duplicate day with a 12-day difference appropriate both for changing from an Asian date to an American date (equivalent to moving the IDL from the east to the west of Alaska) and for changing from the Julian calendar to the Gregorian calendar during the 19th century.
History of time in the United States
After the war its use varied among states and localities. The Uniform Time Act of 1966 provided standardization in the dates of beginning and end of daylight time in the U.S. but allowed for local exemptions from its observance. The act also continued the authority of the ICC over time zone boundaries. In subsequent years, the United States Congress transferred the authority over time zones to the U.S. Department of Transportation (DOT), modified (several times) the beginning date of daylight time, and renamed the three westernmost time zones.
Time zone
On November 2, 1868, the then British colony of New Zealand officially adopted a standard time to be observed throughout the colony, and was perhaps the first country to do so. It was based on the longitude East of Greenwich, that is 11 hours 30 minutes ahead of GMT. This standard was known as New Zealand Mean Time.
UTC+14:00
Alaska (Russian America) had local times from to UTC+15:10 until 1867 (UTC was introduced in 1960). These times were local mean times and not time zones.
East Coast bias
The North American continent is divided into seven time zones, spanning 6½ hours from Alaska to Newfoundland. Most of the continent's population (including all of the major professional sports teams) is concentrated in the four time zones of the contiguous United States and Canada west of the Maritimes; this, however, still poses a significant obstacle in that the easternmost sports teams are a full three hours ahead of their western counterparts. For sports that play in prime time according to local time zones (as is the case with ice hockey, baseball, and basketball), this can result in games played on the West Coast starting after 10 p.m. Eastern time (and not ending until around or after 1 a.m.), while the East is sleeping and after printing deadlines for the next day's newspapers have passed. Gennaro Filice of SI.com wrote that Major League Baseball's West Coast night games are ending as "the country's most influential scribes are catching Z after Z." John Buccigross of ESPN notes that a lot of people in the East are asleep when National Hockey League's West night games are going on, resulting in lower television ratings for those West Coast games, which in turn contributes to the lack of national broadcasts of West games.
Daylight saving time in the United States
During World War I, in an effort to conserve fuel, Germany began observing DST on May 1, 1916. The rest of Europe soon followed. The plan was not adopted in the United States until the Standard Time Act of March 19, 1918, which confirmed the existing standard time zone system and set summer DST to begin on March 31, 1918 (reverting October 27). The idea was unpopular and Congress abolished DST after the war, overriding President Woodrow Wilson's veto. DST became a local option and was observed in some states until World War II, when President Franklin Roosevelt instituted year-round DST, called "War Time", on February 9, 1942. It lasted until the last Sunday (the 30th) in September 1945. After 1945 many states and cities east of the Mississippi River (and mostly north of the Ohio and Potomac rivers) adopted summer DST.
NickMom
The block launched with heavy controversy. As Nick Jr. operated on only one feed that broadcast on a default Eastern Time Zone schedule without a secondary feed for the Pacific Time Zone, NickMom programming started at 7 p.m. Pacific Time, and in time zones further west outside the continental United States, 6 p.m. in the Alaska Time Zone, and 5 p.m. in the Hawaii-Aleutian Time Zone (4 p.m. from mid-March to early November, as Hawaii does not observe DST). Many parents found the scheduling inappropriate, given the supposed sexual, coarse, and child-bashing humor, and uncensored light profanity of the network's launch schedule of programming. Parents also felt that the purpose and lure of the network with full-time preschool programming was nullified in the pursuit of increasing ratings with content not meant for children. The inappropriate scheduling due to one feed was rectified in mid-February 2013, when VMN launched a second Pacific Time Zone-based feed for Nick Jr. which also applied to NickMom.
Standard Time Act
The Standard Time Act of 1918, also known as the Calder Act, was the first United States federal law implementing Standard time and Daylight saving time in the United States. It authorized the Interstate Commerce Commission to define each time zone.
Geodetic datum
The North American Datum of 1927 (NAD 27) is "the horizontal control datum for the United States that was defined by a location and azimuth on the Clarke spheroid of 1866, with origin at (the survey station) Meades Ranch (Kansas)." ... The geoidal height at Meades Ranch was assumed to be zero, as sufficient gravity data was not available, and this was needed to relate surface measurements to the datum. "Geodetic positions on the North American Datum of 1927 were derived from the (coordinates of and an azimuth at Meades Ranch) through a readjustment of the triangulation of the entire network in which Laplace azimuths were introduced, and the Bowie method was used." (http://www.ngs.noaa.gov/faq.shtml#WhatDatum ) NAD27 is a local referencing system covering North America.
Chamorro Time Zone
Chamorro Standard Time shares the same time as Australian Eastern Standard Time.The Mariana Islands were not part of any time zone legislated by the U.S. Congress until the Chamorro time zone was established by Public Law 106-564 on December 23, 2000. Prior to 2000, Guam's standard time was based on territorial Public Law 5-25 (1959) which designated the time Guam Standard Time. The law (Guam Code Annotated, Title 1, Section 1010) was established long before the Northern Mariana Islands came under U.S. sovereignty in 1986, and still remains in the book today despite federal overlap.
Charles F. Dowd
Charles F. Dowd (1825–1904) was a co-principal (with his wife Harriet M. Dowd) of the Temple Grove Ladies Seminary (now Skidmore College) in Saratoga Springs, New York. He was the first person to propose multiple time zones for any country, those for the railways of the United States. He did not propose their extension to the entire world, which was suggested by the Italian mathematician Quirico Filopanti, and championed by the Canadian engineer Sandford Fleming.
Time in Chile
"Summer time in Chile", also known as "daylight saving time (DST) in Chile" was used in Chile from 1968 to 2014 & 2016-present. The time zone "Chile Summer Time (CLST)" was used on the mainland with the offset and "Easter Island Summer Time (EASST)" was used on Easter Island with the offset . In mainland Chile, time was changed at on a Saturday, i.e. at 0:00 on the following Sunday. In Easter Island, time was changed at 20:00 on a Saturday. In 2015, the time offset used in this time zone eventually became the only time zone in Chile.