Why are the 24 solar terms in the solar calendar not in the lunar calendar?

China was an agricultural society in ancient times, and the climate had a very important influence on farming, so the ancients in China paid great attention to the study of climate change. After long-term observation and summary, the climate change in the northern hemisphere is divided into 24 situations and the actual length of day and night, and the 24 solar terms is formulated. According to the theory of geography and meteorology, the fundamental reason of the earth's climate change is the change of sunshine, which is related to the relative position of the earth and the sun, that is, the periodic change of climate corresponds to the solar calendar. Therefore, the 24 solar terms are consistent with the solar calendar.

In fact, the lunar calendar should be called (lunar) calendar, which is calculated according to the change of the moon's circle and circle. It has little direct relationship with farming, but it has a direct impact on tides. During the full moon, the tides are particularly strong, so fishermen and farmers in the coastal areas of China attach great importance to the lunar calendar in their production.

In ancient China, the observation of astronomical phenomena was mainly the sun, the moon and the stars, and the establishment of the calendar was mainly the observation of astronomical phenomena. As the old saying goes, the change of the sky is a reflection. So the main calendar in ancient China was the lunar calendar. The solar calendar was introduced and used only after the development of western science and technology and its influence on China.

Because the lunar calendar and the solar calendar have different calendar bases, that is, people record dates in different periods in solar terms, so the method of adding leap months is adopted to make adjustments. At the same time, because there is no corresponding relationship between the lunar calendar and solar terms, solar terms belong to solar terms, and the lunar calendar belongs to lunar calendar.