The formulation of the 24 solar terms is based on the application of ().

The formulation of the 24 solar terms is based on the application of the middle and lower reaches of the Yellow River.

Twenty-four solar terms are special festivals in the calendar to express natural rhythm changes and establish "December construction". Four years old, three months in spring, summer, autumn and winter, two solar terms each month, each solar term has its own unique meaning. Twenty-four solar terms accurately reflect the change of natural rhythm and play an extremely important role in people's daily life.

It is not only a seasonal system that guides agricultural production, but also a folk system that contains rich folk customs. The twenty-four solar terms contain a long cultural connotation and historical accumulation, and are an important part of the long history and culture of the Chinese nation.

"Twenty-four solar terms" is the product of ancient farming civilization. It is a knowledge system formed by ancient ancestors following the farming season and observing the movement of celestial bodies to understand the changing laws of seasons, climate and phenology in a year. The twenty-four solar terms were originally formulated according to the changes of stars. The Big Dipper rotates once and bucket handle rotates once clockwise, which is called one of the "years" (Figure).

The current "twenty-four solar terms" are formulated according to the position of the sun on the return to the ecliptic, that is, the annual movement track of the sun is divided into 24 equal parts, each 15 is 1, and each 1 is a solar term, starting in beginning of spring and ending in severe cold.

Through historical development, the lunar calendar absorbed the solar terms of the dry calendar as a supplement to the calendar, and adjusted it to conform to the tropic year through the leap method, forming a combined calendar of yin and yang, and the "twenty-four solar terms" became an important part of the lunar calendar. In the field of international meteorology, the 24 solar terms are known as "the fifth invention of China". 2016165438+1October 30th, the 24 solar terms were officially listed in the representative list of UNESCO and human intangible cultural heritage.