Why is winter the solstice in the solar calendar?

Twenty-four solar terms are in the solar calendar.

Twelve months a year.

There are two solar terms per month on average.

The winter solstice is the 10 solar term around 65438+February 22nd every year.

On this day, the sun shines directly on the Tropic of Capricorn, and it is extremely night in the Arctic Circle and extremely day in the Antarctic Circle.

It is obviously related to the sun, so it should be calculated according to the solar calendar, not the moon, so it should not be calculated according to the lunar calendar.

As for when it was determined, some of our ancestors can be traced back to the Qin and Han Dynasties.