What years are there in leap September?

The years of leap September are: 1737, 1756, 1832, 20 14, 2 109, 2204, 2223, 2576, 2720, 220.

Leap September is a kind of leap month, and the time interval of each occurrence is not fixed.

Before and after 2 1 century, leap months were relatively rare in September, and there were no leap months in the 20th, 24th, 25th and 27th centuries. In the 200 years before 2020, there will be only 1832 in the19th century, only 2014th year in the 2 1 century, and the 22nd century will appear in 2 109.

Specific calculation rules of leap month

There are 24 solar terms in ancient Chinese calendar, which are divided into solar terms and neutral atmosphere. The first month of the lunar calendar is called solar terms, and after the middle of the month it is called qi. However, in the Gregorian calendar, the average length of the two solar terms is 30.5 days, while the lunar calendar has only 29.5 days per month, with a difference of 1 day. So the monthly neutral atmosphere will be 1-2 days later than last month. In the long run, there will always be a month with only solar terms and no neutral atmosphere.

In this regard, the ancients in China adopted the method of setting leap months. If a lunar month has only solar terms and no neutral atmosphere, the calendar will take that month as the leap month of last month.