Are the 24 solar terms calculated according to the lunar calendar or the solar calendar?

The 24 solar terms are calculated according to the lunar calendar.

Lunar calendar is a calendar handed down from ancient times in China to guide agricultural production, so it is called lunar calendar. In the lunar calendar based on the ancient lunar calendar, some signs convenient for agricultural production have been added, including some solar calendar knowledge, such as the 24 solar terms in the trunk calendar, so it is a calendar combining yin and yang.

Twenty-four solar terms are special festivals in the trunk and branch calendars, which indicate the change of natural rhythm and establish the "December construction". At first, it was based on the changing stars. The Big Dipper rotates in cycles, and bucket handle rotates in four directions: east, south, west and north, which is called one of the "years old". Each rotation cycle begins in beginning of spring and ends in Great Cold.

Introduction of solar calendar

Lunar calendar refers to the calendar arranged according to the moon phase cycle, with the moon circling the earth as January. In China, the moon is also called the "lunar calendar", so the calendar with the moon as the reference is called the lunar calendar. The moon in the lunar calendar is called the new moon. Gregorian calendar, as its name implies, is a common calendar in most countries in the world. It originated from a calendar approved by Pope Gregory XIII in 1582 and is one of the solar calendars.

The solar calendar is based on the movement period of the earth's revolution, and it defines a year according to the earth's orbit around the sun. In ancient China, there was no knowledge that Heliocentrism and the earth revolved around the sun, so the relative motion of the sun was taken as the research object, so it was called the solar calendar.