Is there a fixed date for the winter solstice? How is the date of winter solstice determined?

The solstice of winter is coming soon. I think the date of winter solstice is similar every year. I wonder if the time of winter solstice is fixed every year.

Is there a fixed date for the winter solstice?

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The winter solstice is not only the 22nd of the 24 solar terms, but also one of the eight traditional seasons in China. It is considered as a big festival in winter. In ancient times, there was a saying that the solstice in winter was as big as a year, so there were different ways to celebrate it every winter. The date is not fixed on a certain day, and generally falls on the Gregorian calendar 65438+February 2 1-23 every year.

Take the date of winter solstice in 2020 as an example, the time is 65438+February 2 1 in Gregorian calendar, while the date of winter solstice in 20 19 is 65438+February 22.

When is the solstice in the winter of 2020?

The winter solstice in 2020 is the seventh day of the sixth lunar month 1 1.

The date of the winter solstice in the lunar calendar is only 165438+ 10. There is still some time before the Chinese New Year, but the weather is getting colder and colder. In order to keep out the cold, people will eat all kinds of food to nourish winter, such as jiaozi in the north, Chaoshan dumplings, Taizhou dumplings in the southeast, Hefei pumpkin pie, Ningbo sweet potato soup, Tengzhou mutton soup, Jiangnan rice, and so on.

Why is the winter solstice not calculated according to the lunar calendar?

Because the date of solar terms is relatively fixed in the solar calendar.

Because the lunar calendar in China is a kind of "yin and yang calendar", which is based on the movement of the sun and the moon, it can't fully reflect the solar cycle. However, China is an agricultural society, and agriculture needs to know the movement of the sun strictly, so the "twenty-four solar terms" which reflect the solar cycle alone are added to the calendar. Most of the 24 solar terms are actually not about the movement of the sun, but about the "phenology". Because phenology changes due to cold and warm changes, it is always related to the annual movement of the sun, so the 24 solar terms are calculated according to the annual apparent movement of the sun on the ecliptic. The solar calendar is the "solar calendar", which is revised according to the changes of the sun. The earth revolves around the sun for one year, so the solar term from the winter solstice is calculated according to the solar calendar, and the date of this solar term is relatively fixed.

When is the date of the winter solstice?

The 24 solar terms are divided according to the position of the sun on the ecliptic.

The sun starts from the vernal equinox, and every advance 15 degrees is a solar term; After a week's operation, I returned to the vernal equinox, which is a tropical year with 360 degrees, so it is divided into 24 solar terms, and the longitude of the sun is 270 degrees from the winter solstice. On the solstice of winter, the sun shines almost directly on the tropic of Capricorn, and the northern hemisphere has the shortest day and the longest night, and it begins to enter several cold days. Astronomy stipulates that this day is the beginning of winter in the northern hemisphere. From winter to the future, the direct sunlight position gradually moves northward, and the daytime in the northern hemisphere gradually becomes longer.