How did the solar term Song come from?

Solar term song can be said to be the wisdom summed up by our working people in the long-term labor practice, and the practical skills on climate summed up by our ancestors. The full text is as follows:

The spring rain shakes the spring and clears the valley, and the summer is full of mountains and summers.

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

The two festivals remain unchanged every month, with a maximum difference of one or two days.

The first half of the year is June 2 1 day, and the second half is August 23.

The first two sentences are abbreviations of the names of solar terms, and the last two sentences are descriptions of the specific time of each solar term.

First, the first two sentences represent each solar term, and the twenty-four solar terms are summarized in two sentences.

"Spring rains begin with spring, and Valley Clearing Day" represents solar terms such as beginning of spring, rain, sting, vernal equinox, Qingming and Grain Rain, mainly in spring. And "Summer Man Mang Xia Shu Lian" stands for Long Summer, Xiaoman, Mangzhong, Summer Solstice, Slight Summer and Great Summer, all of which are solar terms in summer. By analogy, "autumn dew, autumn frost" and "winter snow and winter slight cold" respectively represent the solar terms of beginning of autumn, early summer, white dew, autumn equinox, cold dew and early frost, as well as beginning of winter, light snow, heavy snow, winter solstice, slight cold and severe cold.

Twenty-four solar terms depend on the season, and each season includes six solar terms. This division is very uniform, dividing a year into 4624 solar terms.

Second, the last two sentences mainly talk about the specific date of each solar term. Of course, this is calculated according to the lunar calendar.

"The two festivals will not change every month, at most one or two days apart." This sentence means that there are two solar terms every month on average, and the time of this solar term is almost the same every year, and it is only a day or two at most. Next, "the first half of the year is June 2 1 day, and the second half is August 23." This sentence clearly points out the time of each solar term. The solar terms in the first half of the year are basically on the sixth and twenty-first day of each month, and the solar terms in the second half are basically on the eighth and twenty-third day of each month.

With such a specific description, everyone can immediately calculate the completeness from each person's time change, which is really convenient.

In ancient times, people had nothing special to record climate change. Ordinary working people want to know when it is suitable for farming and harvesting, relying entirely on the wisdom handed down from the older generation. So in the long-term labor practice, everyone summed up such a song of 24 solar terms.