What is the coldest day of the year?

Astronomical experts say that the slight cold and severe cold periods in most parts of China are generally the coldest. As the saying goes, the cold is in the "March 9". "Sanjiu" is mostly from 65438+1October 9 to 17, which is also within the slight cold solar terms. The reason why it is cold before and after the slight cold is that there are frequent strong cold air and cold front in 5438+1October in early June.

In the mild cold season, the average temperature in most parts of North China is generally around -5℃, and the extreme minimum temperature is below-15℃. At this time, the average temperature in Northeast China is around -30℃, the extreme minimum temperature can be as low as -50℃, and the average maximum temperature in the afternoon is only -20℃.

Winter solstice

Although the sunshine in the northern hemisphere is the least, it is not necessarily the coldest day on the winter solstice. The solstice in winter is the shortest day in a year.

As the saying goes, "March and September are cold and mid-September is hot", which means March and September should be the coldest, but it is also related to the morning and evening in beginning of spring. This is a complicated question with no definite answer. When it is coldest is uncertain. But it must be in winter.

Climate is affected by many factors, besides latitude, there are topography, ocean currents, atmosphere (that is, the above-mentioned surface heating to atmospheric heating) and so on.

Take the typical continental monsoon climate in China as an example. An important reason for the lowest temperature and coldest climate during the Great Cold to beginning of spring is the atmospheric movement. The westerly monsoon pushes to the distant ocean with overwhelming advantage, resulting in a continental climate with low temperature, drought and little rain.