When is the solstice in winter?

The winter solstice is a day of Gregorian calendar 65438+February 2 1, 22, 23, every year. In the Yellow River basin, the day with the shortest day is regarded as the winter solstice, and the date between the winter solstice and the next winter solstice is divided into twelve equal parts, which is called "Zhongqi", and then the dates between adjacent "Zhongqi" are divided into equal parts, which is called "solar terms"; On average, there is a "neutral gas" and a "solar term" every month, which are collectively called "24 solar terms". The winter solstice is the 22nd of the 24 solar terms, and the solar calendar reaches 270.

The solar terms measured by the "average time method" rank the winter solstice at the top of the "twenty-four solar terms", and the interval of each solar term is 15 days. The uneven speed of the sun on the ecliptic is not considered in the calculation. Among the solar terms measured by photogrammetry, the day with the longest shadow in a year is the winter solstice.

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 elevation angle of the sun 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 the turning point of direct sunlight returning to the north. After this day, it went back, and the direct sunlight began to move northward from the Tropic of Capricorn (23 26' s), and the sunlight in the northern hemisphere (China is located in the northern hemisphere) increased day by day.