What is the meaning of the 24 solar terms Song Dynasty?

The twenty-four solar terms are: Spring rains shock spring and clear valleys, and summer is full of summer. Autumn dew, autumn frost, little snow in winter and cold in winter. The two festivals remain unchanged every month, with a maximum difference of one or two days. The first half of the year is June 2 1 day, and the second half is August 23.

The corresponding solar terms of "Spring Rain Begins in Spring and Valley Clearing Day" are: beginning of spring, Spring Rain, Sting, Equinox, Qingming and Grain Rain.

The corresponding solar terms of "summer is full and summer is hot" are: long summer, light summer, busy day, summer solstice, little summer and big summer.

The corresponding solar terms of "Autumn Dew and Autumn Frost" are: beginning of autumn, first summer, white dew, autumn equinox, cold dew and first frost.

The corresponding solar terms of "winter snow and winter snow and slight cold" are: beginning of winter, light snow, heavy snow, winter solstice, slight cold and severe cold.

"Two solar terms remain unchanged in January" means that there are two solar terms in every month of the year.

"One or two days at most" means that the difference between the time of each solar term and the predicted time will not exceed one or two days.

"June 2 1 day in the first half of the year" means that the solar terms of each month in the first half of the year are generally on the 6th and 2 1.

"The second half of the year is August 23rd" means that the solar terms of each month in the second half of the year are generally on the 8th and 23rd.