What is winter?
Winter is one of the four seasons, between autumn and spring. Astronomically speaking, it is from February to March, 65438+. China used to refer to the three months from beginning of winter to beginning of spring, and also referred to "October, November and December" in the lunar calendar. The time in the northern and southern hemispheres is different.
In the southern hemisphere, winter is in June, July and August, in the northern hemisphere, winter is in 12, 1 and February. In China, winter begins in early winter and ends in early spring. Westerners generally call winter solstice to spring winter. From the climatological point of view, it is winter when the average temperature is lower than 10℃ for five consecutive days.
Characteristics of winter
Beginning of winter means that winter begins. Traditionally, beginning of winter, with 24 solar terms, is the beginning of winter. In winter, the direct point of the sun moves south to the tropic of Capricorn, and then turns back to the north. In early winter, the sun reaches the longitude of 225 degrees, and the earth is located at declination-16 19', so the height of the sun in the northern hemisphere becomes smaller and the daylight time becomes shorter.
The northern hemisphere gets less and less solar radiation, but it is not very cold, because there is still some energy in the heat stored on the surface in the second half of this year. In winter in Meng, when there is no wind on a sunny day, there is often sunny, warm and comfortable "Xiaoyangchun" weather, and there is a folk saying of "Xiaoyangchun in October".
In some parts of the south, it is generally not very cold in early winter, but with the passage of time, cold air frequently goes south and the temperature gradually drops. The northern region is very cold from winter to spring, and the climate change of several solar terms in winter is not obvious. Snow is the main feature of northern winter.