What do the 24 solar terms in China mean?

The twenty-four solar terms in China refer to the 24 days in a year that divide the seasons:

Beginning of spring, rain, fright, vernal equinox, Qingming, Grain Rain;

Long summer, Xiaoman, Mangzhong, Summer Solstice, Xiaoshu, Dashu;

Beginning of autumn, Chu Shu, Bailu, Autumnal Equinox, Cold Dew, First Frost;

Beginning of winter, light snow, heavy snow. Winter solstice, slight cold, severe cold.

A year is 365 days and 6 hours, divided by 24 knots. Every two solar terms are generally separated by 15 days, and a few are separated by 16 days. Beginning of spring in the solar calendar is on February 4th or 5th every year. At present, the Purple Mountain Observatory can measure 20 knots to hours, that is, every two solar terms are separated by 15 days and 5.25 hours, thus fixing each knot at a certain time, minute and second. Because the orbital plane (equatorial plane) of the earth's rotation is not consistent with the orbital plane (ecliptic plane) of the earth's revolution around the sun (the angle between the equatorial plane and the ecliptic plane is about 23.5 degrees, so the tropic of cancer and the tropic of cancer are located at 23.5 degrees south latitude and 23.5 degrees north latitude, and the tropic of cancer refers to the place where the sun is directly shining, which moves back and forth between the tropic of cancer and the tropic of cancer), the four seasons on the earth are formed. The sun shines directly on the Tropic of Cancer in winter, the equator in the spring equinox, the tropic of Cancer in summer and the equator in the autumn equinox. So the solstice day in summer is the longest, and the solstice day in winter is the shortest.

There are four formulas behind Xinhua Dictionary, which are easy to remember:

Spring rains shake spring and clear valleys,

Summer is full, summer is summer, summer is summer.

Autumn dew and autumn frost,

It snows in winter, it snows in winter, and it's a little cold in winter.