When the cathode arrives, the sun is the spirit, the sun faces south, the day is short and the shadow is long, so it is called "winter solstice". Where did it come from?

The winter solstice is the year with the shortest day and the longest night in the northern hemisphere. After the solstice in winter, the days will get longer day by day. The ancients said this about the winter solstice: As soon as the cathode arrived, the yang began to grow, the sun went south, the day was short and the shadow was long, so it was called "the winter solstice". After the winter solstice, the climate everywhere has entered the coldest stage, which is often called "entering the ninth". There is a saying in China that "the cold is in the third day, and the heat is in the dog days".

Winter solstice is one of the twenty-four solar terms and one of the most important solar terms. Winter solstice is a solar term divided by astronomy, which was called "short day" and "short day" in ancient times. On the solstice in winter, the sun is at 270 degrees of the yellow meridian, and the sun shines directly on the tropic of Capricorn, which is the shortest place in the northern hemisphere in a year. Accordingly, the winter solstice in the southern hemisphere has the longest day. "Twenty-four solar terms" said: "On November 15th, the gas storage finally came to an end." . "Tong Wei Xiao Zhu Shen": "The fifteenth day after the heavy snow is the winter solstice, in mid-November. Yin and Yang began, and the sky went south and grew up. " "Zunxian Manuscript" said: "The day is south, the day is short, and the shadow is long, so it is called the winter solstice. People who' want' are extremely excellent. " It can be seen that our ancients have long known this.

There is no 10 hour from sunrise to sunset in most parts of southern China. From winter to the future, as the earth orbits the sun, the direct sunlight belt gradually moves northward, making the days in the northern hemisphere gradually longer and the nights gradually shorter.

Although the height of the reference sun is the lowest and the sunshine time is the shortest in winter solstice, the heat absorbed by the ground is more than the heat lost. After the winter solstice, it begins to count to nine, and every nine days is a "nine". Before and after "March 9th", the area was the least hot and the weather was the coldest, so it was said that "March 9th was cold".

Astronomy regards the winter solstice as the beginning of winter, which is obviously late for most parts of China. During the winter solstice, the average temperature in the northwest plateau is generally below 0℃, while it is only about 6℃ to 8℃ in the south. In the low-altitude valley areas in the northwest and south, even in the coldest local area of 65438+1early October, the average temperature is still above 10℃, so it can be said that autumn comes and spring comes, and there is no winter all year round.