Is the winter solstice a fixed date?

The winter solstice is not a fixed date, and the time is 0: 00 to 23: 00 on the Gregorian calendar 65438+February 265438+ every year.

The winter solstice is the 22nd solar term among the 24 solar terms in China, when the sun reaches 270 degrees of the yellow meridian. On the solstice of winter, the sun shines directly on the tropic of Capricorn, and the day is the shortest and the night is the longest in the northern hemisphere. As early as more than 2,500 years ago in the Spring and Autumn Period, China had observed the sun with the earth and determined the winter solstice, which was the earliest of the 24 solar terms.

In all parts of the northern hemisphere, the winter solstice is the shortest day in a year, and the farther north, the shorter the day. 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. For the rest of the northern hemisphere, the winter solstice is also the lowest day at noon in a year.

Meteorological changes in winter solstice

There is a cloud in the ancient poem, "The northwest wind hits a hundred herbs and declines, and it is cold and sunny several times." During the day, the time is shortest, but I see Jin Mei blooming. The winter solstice is the shortest day of the year in the northern hemisphere. After the winter solstice, the direct point of the sun gradually moved northward, the days in the northern hemisphere began to get longer and the height of the sun gradually increased at noon. Therefore, there is a proverb that says, "Eating noodles on the solstice in winter will make the day longer. "

The winter solstice has the shortest day and the longest night. After this day, the days began to get longer and longer. Therefore, the ancients believed that "the winter solstice is the sun, and the sun is quiet with the yin." In other words, the solstice in winter is a time when yin and yang alternate. From then on, Yin Qi declined and Yang Qi began to sprout, which is a sign that winter is over and spring is coming. ?

After the winter solstice, the climate in all parts of China will enter a coldest stage, which is often called "ninth year cold" and "ninth year cold". The so-called "number nine" refers to nine days from the date of winter solstice, which is called "nine". After nine nines, it happens to be 8 1 day, whether it is "nine out" or "nine out". From "September 19th" to "September 9th", the cold winter turned into a warm spring.