How did the twenty-four solar terms come about? The origin of the 24 solar terms.

The solar terms 1 and 24 originated in the Yellow River valley and are the crystallization of the long-term experience and wisdom of the working people in ancient China. As early as the Spring and Autumn Period, solar terms such as mid-spring, mid-summer, mid-autumn and mid-winter were set. After continuous improvement and perfection, by the Qin and Han Dynasties, the 24 solar terms had been completely established.

2. The formation of the 24 solar terms is a gradual process. Yang Quan, a philosopher in the Western Jin Dynasty, recorded in "On Things": "In the past, Shennong began to treat farming, regulate solar terms, and judge cold and heat, thinking that it was a period of morning and evening, so it was a calendar day." These words show that the original intention of setting up solar terms is to "manage farming." The solar term is a year, and about 15 days is a solar term, which is divided into 24 different solar terms.

3. During the Spring and Autumn Period, Shangshu, one of the Five Classics, had the allusion of Emperor Yao ordering people to "measure moderately" and established solar terms such as summer solstice, winter solstice, vernal equinox and autumnal equinox. In Guanzi Zhongqing Collection, solar terms such as spring, summer, autumn and winter have been added. In the Warring States Period, the solar terms in Lv's Spring and Autumn Annals increased to 22, and the solar terms took shape. At the beginning of the Han Dynasty, two solar terms, Xiaoman and Heavy Snow, were added to Huainanzi Astronomical Training, forming a complete solar term system.