What is the concept of twenty-four solar terms?

The twenty-four solar terms are defined according to the position of the earth in the orbit around the sun and belong to the solar calendar. The earth revolves around the sun for 360 degrees, which is 0 degrees at the vernal equinox and 15 degrees at Qingming. After that, every 15 degree is a solar term, and its date is basically fixed in the solar calendar. Twenty-four solar terms are the originality of China's calendar method and one of the brilliant achievements of China's ancient science and culture. According to the date of AD, there are beginning of spring, Rain, Sting, Equinox, Qingming and Grain Rain in spring. In summer, there are long summer, small full, awn seed, summer solstice, light summer heat and great summer heat; In autumn, there are beginning of autumn, first ripe, white dew, autumnal equinox, cold dew and first frost. In winter, there are beginning of winter, light snow, heavy snow, eastward movement, slight cold and severe cold.