In ancient times, 24 solar terms were used to divide seasonal changes. How did it come into being?

As early as the Spring and Autumn Period and the Warring States Period, the working people in China had the concept of the solstice in the south and the solstice in the north. Subsequently, people divided the year into 24 equal parts according to the natural phenomena such as the running position of the sun and the moon at the beginning and middle of the month, the weather and the growth of animals and plants. And give each equal part a proper noun, that is, twenty-four solar terms.

By the end of the Warring States Period, solar terms had eight names: beginning of spring, Equinox, Long Summer, Summer Solstice, beginning of autumn, Equinox, beginning of winter and Winter Solstice. These eight solar terms are the most important of the 24 solar terms.

These eight solar terms mark the change of seasons and clearly divide the four seasons of the year. Later, when the book Huai Nan Zi was published, the names of the 24 solar terms were exactly the same as those of the modern ones.

This is the earliest record of 24 solar terms in the history of China. Textual research on unearthed cultural relics discovered by archaeology shows that solar terms were adopted in the Western Han Dynasty in China. There are eight sections and twenty-four solar terms in Zhou Bi suan Jing in Han Dynasty.

Most of them represent climate change, differences between objects and images, and are closely integrated with agriculture. Therefore, at that time, we can grasp the seasonal changes from the eight solar terms and decide to sow and harvest crops in time.

China has been a country with a very developed agriculture since ancient times. Due to the close relationship between agriculture and meteorology, the ancient working people in China have accumulated rich experience in the relationship between agricultural time and seasonal changes in the long-term agricultural labor practice. For the convenience of memory, connect the words of the 24 solar terms into a rhyme:

Spring rain shocks spring and clear valley days, summer is full of mountains and summer is connected with heat, autumn dew is cold and frost, and winter snow drifts. The formulation of the twenty-four solar terms integrates the knowledge of astronomy, meteorology, crop growth characteristics and so on. It accurately reflects the characteristics of natural forces in a year, so it is still used in agricultural production and is deeply loved by farmers.