The solar term in China is ().

The earth revolves around the sun at 5: 48: 46 every 365 days and rotates once every 24 hours. 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, when the sun is directly at 23.5 degrees north latitude, it is called summer solstice in astronomy; When the sun shines directly at 23.5 degrees 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 solar terms reflecting the changes of the four seasons are: beginning of spring, Spring Equinox, Long Summer, Summer Solstice, beginning of autumn, Autumn Equinox, beginning of winter and Winter Solstice. Among them, beginning of spring, Changsha, beginning of autumn and beginning of winter are called "Li Si", which means the beginning of the four seasons. There are five solar terms reflecting temperature changes: slight summer heat, great summer heat, summer heat, slight cold and severe cold. There are seven solar terms reflecting weather phenomena: rain, Grain Rain, white dew, cold dew, first frost, light snow and heavy snow. There are four solar terms reflecting phenological phenomena: Jing Zhe, Qing Ming, Xiaoman and Mang Zi.