The main basis for the division of the twenty-four solar terms

The current twenty-four solar terms are divided by the "Dingqi method", that is, each solar term corresponds to a certain position that the earth reaches every 15° on the ecliptic; the "Dingqi method" divides The annual movement track of the sun is divided into 24 equal parts, each 15° is an equal part, and each equal part is a solar term, starting from the beginning of spring and ending with the great cold, and the cycle starts again and again.

The twenty-four solar terms are as follows:

The Beginning of Spring, Rain, Waking of Insects, Vernal Equinox, Tomb Sweeping Day, Grain Rain;

The Beginning of Summer, Xiaoman, Ear Grain, Summer Solstice, Minor Heat, and Great Heat ;

The beginning of autumn, the end of summer, white dew, autumnal equinox, cold dew, frost;

The beginning of winter, light snow, heavy snow. Winter solstice, minor cold, major cold.

The twenty-four solar terms reflect the influence of the sun on the earth and belong to the solar calendar. It is a knowledge system formed by observing the annual movement of the sun and understanding the changes in seasons, climate, phenology and other aspects throughout the year.

Extended information

The significance of the spring and autumn equinoxes and the summer and winter solstice

1. The vernal equinox

On the vernal equinox, the sun's direct point is on the equator. The direct point of the sun continues to move north, so the vernal equinox is also called the "rising equinox". During the Spring Equinox, theoretically, day and night are of equal length across the globe. After the Spring Equinox, the days become longer and the nights become shorter in the Northern Hemisphere, while the nights become longer and shorter in the Southern Hemisphere. During the spring equinox, there are no extreme day and night phenomena around the world. After the spring equinox, polar day begins near the North Pole, and the area gradually expands; near the South Pole, polar day ends, and polar night begins, with the area gradually expanding.

2. Autumnal Equinox

The half of autumn. After that, the northern hemisphere becomes shorter and the nights become longer. After the autumnal equinox, it is necessary to deliver manure to plow the fields and actively prepare for sowing wheat, as well as harvesting. This is the busiest period in autumn. Before and after the autumnal equinox, the change of the moon's landing will directly predict the quality of the coming year.

3. Summer Solstice

The summer solstice is a very important solar term for farming. The temperature rises and the weather gets hotter. On the summer solstice, the position where the sun shines directly on the ground reaches the northernmost point of the year. In the northern hemisphere The day length reaches its longest, and the days get longer as you go north. Although the summer solstice has the longest day and the highest sun angle, it is not the hottest time of the year. Because the heat close to the surface is still accumulating at this time and has not reached its maximum.

4. Winter Solstice

On the winter solstice, the sun shines directly on the Tropic of Capricorn. It is the ninth day of the solstice. After that, the weather gradually turns cold. In agricultural production, in addition to continuing to carry out anti-freeze, fertilizer accumulation and other work, we must also pay attention to the safety of people and animals through the winter, and the days will gradually become longer.

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Baidu Encyclopedia—Twenty-Four Solar Terms