The current 24 solar terms are a knowledge system formed by observing the movement of the sun for a year and understanding the changing laws of seasons, climate and phenology in a year. It divides the sun's annual trajectory into 24 equal parts, corresponding to a certain position reached by the sun every time it moves 15 on the ecliptic, and each equal part is a "solar term", so there are two solar terms every month.
The 24 solar terms are actually 24 solar terms, 2 per month. Twenty-four solar terms take the earth's revolution around the sun as a cycle, which basically summarizes the different positions of the sun on the ecliptic at different times of the year, the exact time of cold coming and summer going, the laws of natural phenomena such as rainfall and snowfall, and the time of recording some phenological phenomena in nature.
The start date of the 24 solar terms in China's solar calendar is almost the same as that in the international Gregorian calendar, with a difference of one or two days at most, which is precisely because the solar calendar, like the Gregorian calendar, is based on the fact that the earth revolves around the sun once a year. The trunk calendar is a calendar marked by 60 different heavenly stems and earthly branches.
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Historical story of the twenty-four solar terms
The Han Dynasty absorbed twenty-four solar terms as a supplementary calendar to guide farming, and in the book Huainanzi, the names of twenty-four solar terms are completely consistent with modern times, which is the earliest record of twenty-four solar terms in existing literature.
It is said that the 24 solar terms are based on the time series changes of astronomical phenomena, temperature, precipitation and phenology in the middle and lower reaches of the Yellow River. For other parts of China, the situation described by the same solar term may be quite different. In fact, although "Li Si" can reflect the climate characteristics of the four distinct seasons in the middle and lower reaches of the Yellow River, its specific climate significance is not significant.
In climatology, beginning of spring is usually defined as a day when the daily average temperature is stable above 10℃ every five days, which is inconsistent with the meaning of beginning of spring in the middle and lower reaches of the Yellow River. Only the Lingnan area really enters the spring.
"The dividing line between beginning of spring and China in winter and spring (when the average daily temperature reaches 10 degrees Celsius for five consecutive days, it is counted as spring), from Guilin, Guangxi to Ganzhou, Jiangxi. In the area south of this line, the beginning of spring sometimes smells like spring, but 93% of the land in China is still winter. When it comes to Heilongjiang, it is often long summer and spring, and Grain Rain. The so-called beginning of spring is just a' conception'. "
Each of the 24 solar terms is separated by about half a month, divided into twelve months, and each month has two solar terms. Among the 24 solar terms, "festival" refers to a period of a year, which is a representation of a period of time; And "qi" refers to climate, which is an overview of weather changes.
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, the words are connected into a formula: "Spring rain shocks the clear valley in spring, summer is full and summer is hot, autumn is cold and frost falls, and winter snow is raining."
Baidu encyclopedia-24 solar terms