The division of 24 solar terms in a year is based on

The time when the sun runs along the longitude of the Yellow River from zero 15 degrees is called "a solar term". It runs 360 degrees every year, and * * * experiences 24 solar terms, twice a month. Among them, the first solar term of each month is "solar term", that is, beginning of spring, Jingzhe, Qingming, Changxia, Mangzhong, Xiaoshu, beginning of autumn, Bailu, Hanlu, beginning of winter, Heavy Snow, Xiaohan, etc. 12 solar terms; The second solar term of each month is "Zhongqi", that is, there are 12 solar terms such as rain, vernal equinox, Grain Rain, Xiaoman, summer solstice, great heat, intense heat, autumnal equinox, first frost, light snow, winter solstice and great cold. "solar terms"

While "neutral qi" appears alternately, each lasting 15 days. Now people have called "solar terms" and "neutral gas" solar terms.