Every month has either 30 or 31 days, but February has 28 (leap years are out of scope). February currently has 30 days according to our formula, so an expression equal to 2 when x = 2 would be ideal for subtraction.
https://cmcenroe.me/2014/12/05/days-in-month-formula.html
With those tools in mind, let’s get a basic pattern going. Months usually alternate between lengths of 30 and 31 days. We can use x mod 2 to get an alternating pattern of 1 and 0, then just add our constant base number of days: f(x) = 30 + x mod 2.
https://cmcenroe.me/2014/12/05/days-in-month-formula.html
Return to the Top. Month - Day Counter How many months and days are there between two dates. Year - Month - Day - Hour - Minute Counter How many days, hours and minutes are there between two dates and times. Time Menu. Full Year Reference Calendar - Day of the Year and Days left till the End of the Year.
http://www.easysurf.cc/ndate3.htm
How to Remember How Many Days Are in Each Month. Rhyme to remember number of days in each month: 30 days has September, April, June, and November. When short February's done. All the rest have 31... Thirty days hath September, April, June, and November, all the rest have thirty-one.
https://www.theteacherscorner.net/calendars/number-of-days.php
Later in 713BC, Numa Pompilius reformed the calendar of Romulus. He took 1 day from each of the six months with 30 days[1]. Now he made total 57 unaccounted days (51 plus these 6) into two months Ianuarius (January) and Februarius (February). January was given 29 days, and February had 28 days.
https://www.quora.com/What-determines-how-many-days-are-in-a-month
Each knuckle month has 31 days, while each valley month has only 30 days (excepting of course February). February has a smaller leftover amount of 28 or 29 days because pre-45 B.C. it was the last month of the Roman calendar year which started every March.
http://eudesign.com/mnems/dayspcm.htm
DAYS IN EACH MONTH. The number of days in each month has remained unchanged for 2000 years (since 45 B.C. in fact, when Julius Caesar introduced the Julian Calendar). Here's a well-known mnemonic rhyme which has been in existence for over 400 years, to indicate the exact number of days in each different month:
http://eudesign.com/mnems/dayspcm.htm
There you have it, a formula for the number of days in each month using simple arithmetic. So next time you find yourself wondering how many days are in September, just remember to apply f(9). For ease of use, here’s a JavaScript one-liner:
https://cmcenroe.me/2014/12/05/days-in-month-formula.html
The quick answer is 30 days. This is a nice round number that is easy to work with. It also gives you a clue why there are 360 degrees in a circle, 12 hours on the clock, 24 hours in a day, 60 minutes in an hour and 60 seconds in a minute.
https://www.quora.com/What-is-the-average-number-of-days-in-a-month
But a 29½-day month is not convenient for a calendar; a calendar where the date changes in the middle of the day one day out of the month would make things more complicated. So the calendars generally had a 30-day month followed by a 29-day month followed by a 30-day month, and so on.
https://www.quora.com/What-determines-how-many-days-are-in-a-month
the month how many days
Every month has either 30 or 31 days, but February has 28 days. There are either 30 or 31 days in every month but February has 28 days. Every month has either 30 or 31 days, but February has 28 and in leap years are out of scope.