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.
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.