Leap may occur every few years. .

Leap may occur every 8 years or 1 1 year.

Around 2 1 century, leap may is the leap month with the highest frequency (but it is not static, and then the frequency of leap may will gradually decrease from the highest with the passage of time), and it usually appears once every 8 years or 1 1 year.

Leap months are calculated, and they are not fixed in the order of months in a year. There are more leap months in April, May and June, and fewer leap months in September and October, especially in 1 1, 12 and the first month. In that year, the lunar calendar had 13 months, which was called leap month year.

In the lunar calendar, the length of the first lunar month (29.5306 days) is the average of one month, which is 65438+February in the whole year, which is about 10 and 2 1 hour different from the tropic year (365.2422 days), so it is leap in turn, one month in three years, two months in five years and seven months in nineteen years. A leap month added after a certain month is called a leap month.

Extended data:

The lunar leap month is to coordinate the contradiction between the tropic year and the lunar year.

What is the contradiction between the tropic year and the lunar year? The total length of the tropic year is 365.2422 days, and the length of the first lunar month is 29.5306 days.

12 lunar months constitute lunar years, with a length of 29.5306× 12=354.3546 days, which is 10.88 days less than the regression and about 1/kloc-0 less than the monthly 0.9 1 day.

Accordingly, if the Spring Festival in one year of the lunar calendar is a snowy winter, the Spring Festival in the next year will be 1 1 day earlier than the season, and 16 Lunar New Year will appear in the hot summer.

If the lunar year consists of thirteen lunar months, the length is 29.5306× 13=383.8978 days, which is more than the tropic year 18 days.

If the calendar is made according to the above regulations, there will be a strange phenomenon that the weather is inconsistent with the calendar and the time order is disordered and reversed-this is contradiction.

In order to overcome this shortcoming, our ancestors found the method of "leap month" on the basis of astronomical observation, ensuring that the first month to March is spring, April to June is summer, July to September is autumn, and October to December is winter, while ensuring that the first year of the lunar calendar is in late winter and early spring.

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