What are the meanings of "621" and "823" in the songs of the 24 solar terms?

Sixty-one: sixth and twenty-first (20: pronounced niàn means twenty)

August 23rd: 8th and 23rd (20: pronounced niàn means 20)

In the first half of the year, there were two solar terms every month. The first solar term was around 6th, and the second solar term was around 2 1. In the second half of the year, there are two festivals every month. The first festival is around the 8th, and the second festival is around the 23rd.

"Twenty-four solar term song" is a poem compiled for the convenience of remembering the twenty-four solar terms in the ancient calendar of China. Solar terms refer to 24 seasons and climate. It is a calendar formulated by China in ancient times to express seasonal changes and guide agriculture. It is the crystallization of the long-term experience and wisdom of the ancient working people in China.

The folk songs are as follows:

Spring rains shake the spring and clear the valley, and summer is full of mountains and summers.

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

The two festivals are the same every month, with a difference of one or two days at most.

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