The fact that Mid-Autumn Festival and National Day fall on the same day is mainly the result of leap month. Zhao Zhi Heng, director of Tianjin Astronomical Society, said: According to the Chinese lunar calendar, there are 30 days in the big month and 29 days in the small month, which is 354 days or 355 days less than that in a tropical year. Four years later, 1 month was missing. Over time, there will be a strange phenomenon of time sequence and time disorder.

In order to solve this problem, the method of adding "leap month" is adopted. The leap month occurred in June this year, which not only delayed Valentine's Day in China, but also delayed the Mid-Autumn Festival. In addition, the Lunar Mid-Autumn Festival generally occurs between September 7th and June 6th in the solar calendar 10, resulting in the calendar phenomenon that the Mid-Autumn Festival coincides with the National Day.

Extended data

Mid-Autumn Festival and National Day in the same year:1982,2001,2020,2031. In 200 1 year, the national day of the Gregorian calendar 10 coincides with the Mid-Autumn Festival on August 15 of the lunar calendar, and the national day of 19 coincides with the Mid-Autumn Festival of 1982.

Further on, the Mid-Autumn Festival of 19 and 1963 is 10, and the difference is only 1 day. Whether it is a lunar month or a solar year, their exact dates are not integers but decimals. 19 There is still a slight difference between the lunar calendar and the solar calendar. After decades or even hundreds of years of accumulation,