The Gregorian calendar year is a whole hundred years. How many times must a leap year be?
The establishment of leap year is to make up for the time difference between the number of days in a year and the actual period of revolution of the earth caused by man-made calendar regulations. The year to make up for the time difference is leap year. Leap year * * * has 366 days (February is 1- 1 day, 29 days, 3 1 day, 30 days, 3 1 day, 3 1 day respectively).
Where there is a leap day in the solar calendar (February 29); Leap surplus (leap surplus). The time difference between the lunar calendar and the tropic year); Please note that leap year (a term in the Gregorian calendar) is not directly related to leap month (a term in the lunar calendar). The Gregorian calendar has only leap years and peace years, with 365 days in a normal year and 366 days in a leap year (one more day in February). There may also be leap months in a normal year (for example, 20 17 is a normal year, and there are leap months and leap months in the lunar calendar).
Extended data:
The Gregorian calendar has an average of only 365 days a year, which is about 0.2422 days shorter than the tropical year, and the remaining time is about one day every four years. So 1 day is added at the end of February of the fourth year, making the calendar year of that year 366 days, and this year is a leap year.
The month of the leap month is inferred according to the laws of the lunar calendar, which is mainly determined according to the coincidence with the 24 solar terms of the lunar calendar. The year with leap month is 13 months, and the calendar year is 383 to 385 days. This year is also called leap year.
The current Gregorian calendar has 97 leap years every 400 years. According to a leap year every four years, it will count as 0.0078 days per year on average, so after 400 years, it will count as 3 days. So every 400 years, three leap years will be reduced.
Baidu encyclopedia-leap year