How did the twenty-four solar terms come into being?

The lunar calendar of the Han Dynasty divides the tropic year (a solar calendar) into 24 solar terms, each of which is a little more than fifteen days. This is the process of the 24 solar terms.

Twenty-four solar terms originated from the China calendar. In China calendar, the solar calendar and the lunar calendar are different. The solar calendar is based on the movement of the sun and stars, and there are 365 days in a year. The lunar calendar is calculated according to the movement of the moon, and there are only 354 days in a year, that is, the difference between a lunar year and a solar year is 1 1 day.

The biggest difference between the lunar calendar and the solar calendar is that it cannot accurately reflect the seasonal changes. Agricultural production must follow seasonal changes, and for the smooth progress of agricultural production, it must be guided by the solar calendar.

The names of the twenty-four solar terms were first seen in Tian Zi Xun of Huainan in Han Dynasty, and their names all reflected the changes of solar terms and the situation of crop growth. Twenty-four solar terms are divided into twelve solar terms and twelve middle qi. Solar terms are referred to as solar terms, and the first solar term of each month is called solar terms. Zhong Qi is called Qi for short, and the second solar term of each month is called Qi.

In order to facilitate memory, people weave the 24 solar terms into a formula:

The spring rain surprised the spring and the valley, and the summer was busy and the summer was even hot.

Autumn dew, autumn frost, little snow in winter and cold in winter.