Which solar term is the shortest in a day?

On the day of winter solstice, the sun moves to 270 degrees of the yellow meridian (winter solstice), and the position of the sun directly on the ground reaches the southernmost point of the year. The sun is almost direct to the Tropic of Capricorn (also known as the winter solstice daily line), and the sun is most biased towards the northern hemisphere. Therefore, the winter solstice is the shortest day in all parts of the northern hemisphere in a year, and the farther north, the shorter the day.

For all parts of the northern hemisphere, the winter solstice is also the day with the lowest sun height at noon all year round. North of the Arctic Circle, the sun is below the horizon all day, which is the widest day of the year in the northern hemisphere. In winter solstice, the northern hemisphere gets the least solar radiation, which is about 50% less than that in the southern hemisphere in hot summer.

The winter solstice is the southernmost day of the year. After this day, the direct point of the sun began to move northward from the tropic of Capricorn, and the length of the day in the northern hemisphere began to increase gradually, and the height of the sun also increased gradually at noon.

Extended data:

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 huge climate difference in China, this climatic winter 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").

References:

Baidu encyclopedia-winter solstice