How to determine the date of Qingming every year

Tomb-Sweeping Day is at the turn of mid-spring and late spring, that is, after the winter solstice 106 days.

One revolution of the earth is 360 degrees of the yellow meridian, and when the earth reaches zero degrees of the yellow meridian, it is designated as the vernal equinox, and then there is a solar term every time it runs 15 degrees, and there are 24 solar terms in * * *. Therefore, the dates of solar terms in the solar calendar are fixed, and there will be two-day differences in leap years. So Qingming is between April 4th and 6th in the solar calendar, mostly on the 5th.

It is not fixed on April 5 of the solar calendar, nor is it determined by the lunar calendar. ? The vernal equinox changes with the rotation of the earth. The earth's daily rotation is not 24 hours, but 23 hours and 56 minutes, and it will be reduced by one day every four years, thus affecting the time of solar terms. According to this law, it is derived.

Qingming is one of the 24 solar terms in the summer calendar. After the vernal equinox, before Grain Rain. "Almanac": "On the fifteenth day after the vernal equinox, the bucket refers to the ding, which is used for Qingming. Everything is clean and bright, and it covers the time (the temperature rises, the fog in the south is less, the sand in the north disappears, and the air permeability is good), hence the name."

Astronomical time: the sun is located at the longitude of the yellow meridian 15 degrees, and crosses the intersection point on the 4th to 6th day.

Tomb-Sweeping Day is one of the important "eight festivals a year" in China. Generally, it is around April 5 of the Gregorian calendar, and the festival is very long. There are two sayings: 8 days before 10 and 10 days before 10, and these 20 days belong to Tomb-Sweeping Day. Tomb-Sweeping Day originally meant grave-sweeping day, and the government of the Republic of China designated 15 days after the vernal equinox in 935 as a national holiday, also known as the national grave-sweeping day.

In addition to paying attention to hiking and sweeping graves, Tomb-Sweeping Day also has a series of customs and sports activities, such as banning fire, swinging, cuju, playing polo and inserting willows.

References:

Baidu Encyclopedia-Qingming