On a "ecliptic" with a circumference of 360 degrees (the apparent path of the sun on the celestial sphere for one year), it is divided into 24 equal parts, each equal part is 15 degrees, starting at 0 degrees in spring, and arranged according to the degrees of the ecliptic.
That is, the sun starts from the vernal equinox, that is, the longitude of the Yellow River is zero. At this moment, the sun shines vertically on the equator, and every advance of 15 degrees is a solar term; A week after the operation, I returned to the vernal equinox, which is a year of return. The twenty-four solar terms are exactly 360 degrees, and every time the sun runs 15 degrees on the ecliptic, it is a "solar term".
Climate type:
Twenty-four solar terms are the product of agricultural civilization and the knowledge system formed by ancient ancestors by observing celestial movement combined with geographical climate and phenological laws. Agricultural production is closely related to geographical and climatic resources, and superior geographical and climatic resources are important conditions for the birth of agricultural civilization.
China is located in the east of Asia-Europe continent and the west coast of the Pacific Ocean, with great differences in thermal properties between land and sea, forming the most typical monsoon climate in the world. Monsoon climate is a mixture of continental climate and maritime climate.
In winter, affected by the dry and cold air flow in the inland, the weather is cold, dry and rainy; In summer, it is hot, humid and rainy because of the warm and humid air currents in the ocean. Adequate sunshine, abundant precipitation, high temperature and humid rain and heat are very superior climate resources in China. The high temperature period is consistent with the rainy season, and the water and heat are well coordinated, which is very beneficial to the growth of crops.