When is the winter solstice of 202 1, and how to calculate the solar term time of winter solstice?

The solar terms of 1 and 202 1 winter solstice are 23: 59: 9 of Gregorian calendar 202 1 and February 2 1, which is 1 1 month 18 of the lunar calendar.

2. How to calculate the solar term time of winter solstice?

Pointing to the bucket, the longitude of the sun is 270, which is the solstice in winter. The first month is the first month, November is the second month, and the winter solstice is the 22nd of the 24 solar terms. The winter solstice usually falls on the second day of Gregorian calendar 65438+February 2 1 or 65438+February 22.

Note: The average time method (used before 1645) does not consider the uneven speed of the sun moving on the ecliptic, which is different from the constant gas method (used since 1645), and the specific intersection time of each solar term is also different.

Astronomically, the "winter solstice" is the turning point of the sun's southward movement. Because the earth is located near the perihelion in winter, and its running speed is slightly faster, the time of direct sunlight in the southern hemisphere in a year is about 8 days shorter than that in the northern hemisphere, so the winter in the northern hemisphere is slightly shorter than that in summer.