How many days are there in each of the 24 solar terms?

The ancients in China divided the sun's annual trajectory into 24 equal parts, each of which was divided into a solar term, and each solar term had three cycles, each of which was five days. According to the law of the operation of heaven and earth, the ancients determined the starting point and ending point of the four-season cycle and divided the 24 solar terms. The trajectory of the sun in a year is divided into 24 equal parts, each of which is a "solar term", collectively called "twenty-four solar terms".

Because it takes 365 days for the earth to go around the sun, there is a solar term every fifteen days, and each solar term represents different changes in climate, phenology and time.

"Twenty-four solar terms" reflect the influence of the sun on the earth and belong to the solar calendar category. It is a knowledge system formed by observing the movement of the sun in a year and understanding the changing laws of the four seasons, climate and phenology in a year. It not only plays a guiding role in agricultural production, but also affects the food, clothing, housing and transportation of ancient people, and even cultural concepts. The current lunar calendar absorbs the solar terms of the trunk calendar as a supplement to the calendar, and is adjusted to conform to the tropic year through the leap method, forming a combined calendar of yin and yang.

Twenty-four solar terms are not only the time criterion promulgated by successive governments, but also the compass to guide agricultural production and to predict cold, warm, snow and rainy days in people's daily life. In the field of international meteorology, the 24 solar terms are known as "the fifth invention of China". 2016165438+1October 30th, 24 solar terms were officially listed in UNESCO's Representative List of Intangible Cultural Heritage of Humanity.