How to calculate the 24 solar terms?

According to the position of the sun on the ecliptic, 24 seasons and climate are divided, which reflects the natural phenomenon and seasonal characteristics of farming in a certain area of China (represented by the middle and lower reaches of the Yellow River). Namely, beginning of spring, Rain, Sting, Vernal Equinox, Qingming, Grain Rain, Changxia, Xiaoman, Mangzhong, Summer Solstice, Xiaoshu, Dashu, beginning of autumn, Chushu, Bailu, Autumnal Equinox, Cold Dew, First Frost, beginning of winter, Light Snow, Heavy Snow, Winter Solstice, Slight Cold and Severe Cold.

Twenty-four solar terms, a supplementary calendar to guide farming in ancient China, were formed in the Spring and Autumn Period and the Warring States Period. Because the lunar calendar in China is a kind of "yin and yang calendar", which is based on the movement of the sun and the moon, it can't fully reflect the solar cycle. But China is an agricultural society, and agriculture needs a strict understanding of the movement of the sun, so farming is entirely based on the sun. Therefore, the "twenty-four solar terms" that reflect the solar cycle alone are added to the calendar as the standard for determining leap months. Twenty-four solar terms can reflect the changes of seasons, guide agricultural activities and affect the food, clothing, housing and transportation of thousands of families. The twenty-four solar terms are divided according to the position of the sun on the ecliptic (that is, the orbit of the earth around the sun).

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 first half of the year is June 2 1 day, and the second half is August 23. The dates of the two festivals are fixed every month, with a maximum difference of one or two days.