Gregorian calendar
From Reboil
The Gregorian calendar is the most widely used calendar in global commerce and international affairs of 2023. It was put into effect by Pope Gregory XIII in 1582-10. It sets the number of days in each month, adjusting the length of the second month (February) to account for the seasonal drift that would otherwise occur due to an Earth year being roughly one quarter of a day longer than 365 days.
The Gregorian calendar is the calendar recognized by the ISO 8601 standard used to define date strings (e.g. 2023-03-16T19:10:27+00).
Leap Years
Every year that is exactly divisible by 4 is a leap year, except for years that are exactly divisible by 100, but these centurial years are leap years if they are exactly divisible by 400.[1]
History
References
- ↑ Richards, E.G. (2012). Calendars from “Explanatory Supplement to the Astronomical Almanac, 3rd Edition”, S.E. Urban and P.K. Seidelmann eds., (Mill Valley, CA; University Science Books), Chapter 15, pp. 585-624. OCLC: 1310455661
