In which dynasty did the winter solstice solar terms begin?

Winter solstice, also known as solstice and winter festival, has dual connotations of nature and humanity. It is not only an important solar term among the 24 solar terms, but also a traditional folk ancestor worship festival in China. The custom of winter solstice varies in content or details due to different regions. In southern China, there are customs of offering sacrifices to ancestors and enjoying the winter solstice. In northern China, it is a custom to eat jiaozi from winter to Sunday every year.

The winter solstice is the 22nd solar term in the "24 solar terms", and the solar calendar reaches 270 degrees. Every year, the festival is held on 65438+February 2 1-23 in the Gregorian calendar. The solstice in winter is the extreme point of direct sunlight spreading to the south. From winter to the sun, the sun shines directly on the Tropic of Capricorn, and the sun is most inclined to the northern hemisphere, and the solar altitude angle is the smallest. In all parts of the northern hemisphere, the days are the shortest and the nights are the longest.

The solstice in winter is also a turning point for the sun to return directly to the north. After this day, the direct point of the sun will go back. The direct point of the sun will move northward from the Tropic of Capricorn (23 26' s), and the daylight in the northern hemisphere (China is located in the northern hemisphere) will increase day by day.

In winter solstice, although the sun is low and the days are short, the temperature in winter solstice is not the lowest in meteorology. In fact, because there is still "accumulated heat" on the surface, it is usually not very cold before the winter solstice, and the real cold is after the winter solstice.

Because of the great difference in climate in different parts of China, this winter climate is obviously late for most parts of China. The winter solstice marks the beginning of the cold season, and people begin to count to nine to calculate the cold weather (folk proverb: "The summer solstice is the third watch, and the winter solstice is the ninth watch").