The 24 solar terms are very old in China. Why should they correspond to the western solar calendar?

China's lunar calendar is based on the revolution of the moon around the earth.

The twenty-four solar terms divide the period of revolution around the sun into twenty-four points.

Therefore, the time period of the 24 solar terms objectively coincides with the Gregorian calendar, and the date of each solar term is relatively fixed in the Gregorian calendar, and the error before and after is less than 1 day. The Gregorian calendar was not applicable in ancient China, so there was no fixed date for the correspondence between the 24 solar terms and the lunar calendar.