The "Gregorian calendar," often spelled as "Gregorian calendar," is the calendar system most commonly used today worldwide for civil purposes. It was first introduced by Pope Gregory XIII in 1582 as a reform of the Julian calendar. The Gregorian calendar is used by most of the world's countries, including the United States, Canada, and many European nations, for tracking time, scheduling events, and determining dates.
Key features of the Gregorian calendar include:
Leap Years: The Gregorian calendar accounts for the discrepancy between the solar year (the time it takes for the Earth to orbit the sun) and the calendar year. To do this, it adds an extra day, February 29, to the calendar approximately every four years. These years are known as leap years.
Months: The Gregorian calendar has 12 months, with varying lengths: January (31 days), February (28 or 29 days in a leap year), March (31 days), April (30 days), May (31 days), June (30 days), July (31 days), August (31 days), September (30 days), October (31 days), November (30 days), and December (31 days).
Weeks and Days: Each month contains weeks, with a typical week having seven days: Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, and Saturday.
Year Count: The Gregorian calendar's year count is based on the traditional birth year of Jesus Christ. Therefore, it uses the abbreviation AD (Anno Domini) for years after the estimated birth of Jesus and BC (Before Christ) for years before.
The Gregorian calendar is widely used for everyday activities, scheduling events, conducting business, and keeping track of historical and cultural dates. It replaced the Julian calendar, which had an issue with accumulating errors in tracking the solar year, resulting in calendar drift over time. The Gregorian calendar's leap year system is more accurate in aligning the calendar year with the solar year, making it the standard calendar used worldwide tod