What is the coldest solar term in a year?

The coldest solar term in a year is slight cold.

Slight cold is the 23rd solar term among the 24 solar terms, the 5th solar term in winter, the end of the second month of the dry calendar and the beginning of the ugly month. Fighting fingers; The meridian of the sun is 285; It is celebrated from June 5 to 7 in the Gregorian calendar. Cold air is cold for a long time, and slight cold means that the weather is cold but not extreme. Like severe cold, mild heat, severe heat and intense heat, it is a solar term indicating temperature change. The slight cold solar term is characterized by cold, but it is not extremely cold.

In the slight cold season, the direct point of the sun is still in the southern hemisphere, and the heat in the northern hemisphere is still in a state of loss. The heat absorbed during the day is still less than the heat released at night, so the temperature in the northern hemisphere continues to decrease. After the winter solstice, the cold air frequently goes south, and the temperature continues to drop, and the temperature drops to the lowest during the slight cold and severe cold in a year. There is a folk saying, "It's 239 when it's a slight cold, and it's shivering with cold", which shows the cold degree of solar terms.

The difference between north and south of slight cold:

There is a great difference in climate between the north and the south of China, and long-term meteorological records also prove this point: in the north, the slight cold solar terms are colder than the severe cold solar terms; But for most parts of the south, the big cold solar terms are colder than the small ones.

According to the statistics of climatic data, the coldest time in most parts of northern China is June 5438+1mid-October (June 5438+00-20); The annual slight cold solar term starts from 65438+1October 5-7, one solar term is about 15 days, and the middle section is just within the slight cold solar term; So for most parts of the north, slight cold is indeed colder than severe cold. But for most parts of the south, it is the coldest in the great cold solar terms; The severe cold solar term generally starts from 65438+1October 20th (65438+1late October), which is the coldest time of the year in the south.

The slight cold in northern China is colder than the severe cold, because there is relatively little "residual heat" on the surface, which has been released by the slight cold. At this time, the days are short and the nights are long, and the cold air is powerful, which minimizes the temperature. In the great cold, the sun's light and heat increased slightly, so the temperature also increased slightly.

In the south, the surface is hot, and its "residual heat" has not been released until the solar terms are slightly cold, so the temperature has not dropped to the lowest; In the severe cold, the surface "waste heat" is exhausted and it is freezing badly. At this time, the sunlight and heat slightly more than the slight cold will not play much role, and the temperature in the south will be minimized.

Reference to the above content: Baidu Encyclopedia-Slight Cold