The 24 solar terms are calculated according to the solar calendar?

The lunar calendar in China is based on the change of the moon. The longest day in the lunar calendar is 385 days, and the shortest day is 353 days. Moreover, there are many leap months, and many seasons are out of order. Using the lunar calendar to guide agricultural production may miss the season of spring ploughing and autumn harvest. Therefore, according to the seasonal characteristics of each year, the ancients formulated 24 solar terms that are almost consistent with the current Gregorian calendar, such as February 4th in beginning of spring, April 5th in Qingming Festival, and February 22nd in winter solstice 12, in which the winter solstice has the shortest day and the longest night, and the summer solstice has the longest day and the shortest night, and the vernal equinox has the longest day and night. We know that the earth revolves around the sun, with perihelion and apohelion, but the seasons are not determined according to perihelion. In other words, summer is not because the earth is close to the sun, but because it exists all year round, and the season is related to the direct angle of the sun. Summer in the southern hemisphere is winter in the northern hemisphere and summer in the northern hemisphere is winter in the southern hemisphere.

China is a vast country. From south to north, the seasons are different. For example, in March, it is already warm in spring in bloom in the south, and it may still be snowing in the north. So how is this solar term divided? According to the length of a day, the winter solstice is 65438+February 22nd, the summer solstice is June 22nd, the winter solstice is the Tropic of Cancer, and the summer solstice is the Tropic of Cancer, that is, the north latitude is 23 26 ′ 28 ″ 44, so the 24 solar terms are divided according to the Tropic of Cancer. If 24 solar terms is used in the southern hemisphere, it is a solar term disorder.