Why is the Tomb-Sweeping Day gas always at 456? The reason why Qingming Qi is in 456.

1, Qingming is one of the 24 solar terms. Solar term is a knowledge system and social practice formed by observing the movement of the sun in a year, and each node corresponds to a certain position reached by the earth every time it runs 15 on the ecliptic, and understanding the changing laws of seasons and climate in a year.

2. However, the actual length of a tropical year is 365.2422 days, and the Gregorian calendar year is 365 days, which is 0.2422 days more each year. The specific time of solar terms will also be postponed every year. Sometimes a solar term lasts longer than midnight to the next day, but no matter how it changes, the date difference of solar terms will only be within three days, so the Qingming date in the solar calendar will change on April 4, 5 and 6.