Language/Multiple-languages/Culture/Calendars-and-Clocks

This is a list of calendar and timekeeping around the world.

Calendar

name	description
Gregorian calendar	The epoch is the year of presumed birth of Jesus of Nazareth. The start of a year is the presumed day of circumcision of Jesus of Nazareth. There are 12 months in a year. Days for months are 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31. The start of a day is the midnight in Greenwich added or subtracted by multiples of 1 hour, and in some cases further add or subtract 0.5 or 0.25 of hours. The leap day is placed in the second month. There is 1 leap day every 4 years, except when the year is divisible by 100 and not divisible by 400. (There are about 1 leap in 4 years.)
Chinese agricultural calendar	The epoch is the year of presumed enthronement of Yellow Thearch. The start of a year is the presumed day of enthronement of Thearch Shun. There are 12 or 13 months in a year. The first month is the month with winter solstice. There are 29 or 30 days in a month, determined by the moon phase. The first day of a month is the day with new moon. The start of a day is the midnight. Leap month is the first month without a solar term of an even number. (There are about 7 leaps in 19 years.)
Korean agricultural calendar	The epoch is the year of the foundation of Gojoseon. There are 12 or 13 months in a year. The first month is the month with winter solstice. There are 29 or 30 days in a month, determined by the moon phase. The first day of a month is the day with new moon. The start of a day is the midnight. Leap month is the first month without a solar term of an even number. (There are about 7 leaps in 19 years.)
Lunar Hijri calendar	The epoch is the year of Hijrah. There are 12 months in a year. There are 29 or 30 days in a month, determined by the moon phase / There are 30 days in months of an odd number, 29 days in months of an even number. The first day of a month is the day with the first sight of the crescent. The start of a day is at sunset. The leap day is added to the last month. Year with the leap day is the year when the remainder is over 0.5 days. (There are about 11 leaps in 30 years.)
Solar Hijri calendar	The epoch is the year of Hijrah. The start of a year is the vernal equinox. There are 12 months in a year. There are 31 days in the first 6 months, 30 days in the next 5 months, 29 days in the last month. The start of a day is at sunset. The leap day is added to the last month. (There are about 8 leaps in 33 years.)

Timekeeping

name	description
European timekeeping	A day is divided by 12 units ‘hour’ (in English) evenly. An hour is divided by 60 units ‘minute’ (in English) evenly. A minute is divided by 60 units ‘second’ (in English) evenly. A leap second is added to the last minute of a day irregularly.
Chinese timekeeping	A day is divided by 12 units ‘時’ evenly. A 時 is divided into 2 parts: ‘初’, ‘正’ evenly. Every such part is divided by 4 units ‘刻’ evenly.
Thai timekeeping	A day is divided by 4 periods ‘...โมงเช้า’, ‘บ่าย...โมง’, ‘...ทุ่ม’, ‘ตี...’ evenly. Every such period is divided into 6 parts evenly.