What are the 24 solar terms?

24 solar terms is beginning of spring, rain, creep, vernal equinox, Qingming, Grain Rain, Changxia, Xiaoman, Mangzhong, Summer Solstice, Xiaoshu, Dashu, beginning of autumn, Chushu, Bailu, Autumnal Equinox, Cold Dew, First Frost, beginning of winter, Light Snow, Heavy Snow, Winter Solstice, Slight Cold and Severe Cold.

Twenty-four solar terms ("fixed-air method" solar terms) reflect the annual apparent movement of the sun. Because the orbital plane of the earth's rotation is not the same as the equatorial plane, but maintains a certain inclination angle, the position of direct sunlight on the earth is different all year round. In the northern hemisphere, the sun shines directly on the Tropic of Cancer (23 26' north latitude), which is called summer solstice in astronomy. When the sun shines directly on the tropic of Capricorn (23 26' south latitude), it is called the winter solstice; The solstice in summer and the solstice in winter mean that it is halfway between summer and winter.

Twice a year, when the sun shines directly on the equator, it is the vernal equinox and the autumnal equinox, in the middle of spring and autumn. The day is as long as the night. The activity law of the direct solar point is as follows: at the vernal equinox (about March 2 1), the direct solar point is at equator 0, and then moves northward. During the summer solstice (around June 22nd), the direct point of the sun is on the Tropic of Cancer (23 26' N), and then moves south. At the autumnal equinox (around September 23), the direct point of the sun is 0 on the equator, and then it continues to move south. During the winter solstice (around 65438+February 22nd), the direct point of the sun is on the tropic of Capricorn (23 26), and then moves northward.