How is the time period of the 24 solar terms calculated? Is it half a month before and after Boxing Day?

The calculation formula of the twenty-four solar terms is as follows: [y * d+c]-L.

Interpretation of the formula: the last two digits of the number of years are multiplied by 0.2422 plus 3.87, and the whole number is subtracted from the number of leap years.

2 1 century c value =3.87, and in the 22nd century c value =4. 15. For example, the calculation steps of beginning of spring date in 2058 are [58× .0.2422+3.87]-[(58-1)/4] =17-14 = 3, so beginning of spring date is February 3.

24 solar terms refers to the 24 specific solar terms in the China lunar calendar, which are formulated according to the change of the earth's position on the ecliptic (that is, the earth's orbit around the sun), and each solar term corresponds to a certain position reached by the earth every time it runs 15 on the ecliptic.

Twenty-four solar terms, a supplementary calendar, were established in the pre-Qin period in China and completely established in the Han Dynasty to guide farming. It is a knowledge system formed by observing the movement of the sun in a year and understanding the changing laws of the four seasons, climate and phenology in a year. It divides the sun's annual trajectory into 24 equal parts, and each equal part is a solar term, starting from beginning of spring and ending with the great cold. It is not only a time standard promulgated by successive governments, but also a compass to guide agricultural production.