Why is the solstice in winter the coldest day?

In fact, the solstice in winter is not the coldest day. The coldest days are March 9 and April 9 after the winter solstice.

On the solstice of early winter, there is a saying among the people: "1929 does not make moves, walks on the ice in 3949, sees willows along the river in 5969, opens the river in 79, geese come in 89 and flowers bloom in 90." It can be seen that winter solstice is not the coldest day, but the coldest days are 399 and 499.

The winter solstice not only marks the beginning of winter, but also represents the shortest day of the year. On the solstice of winter, the northern hemisphere receives less sunlight than on any other day of the year. The advantage of this is that with the passage of time, the light received every day will be slightly longer than the previous day. But on the negative side, the coldest day of the year is coming. The solstice in winter is not the coldest day, because it is related to the earth.

Although the winter solstice is the shortest day in a year and the earth absorbs the least heat, the earth itself will store some heat and exchange it with the outside world, so there will be a heat dissipation process after the winter solstice. When the local temperature and the outside temperature reach the same level, the temperature will gradually increase. Of course, cold is not only because of the heat exchange between the earth and the outside world, but also because of global climate change. September 9 and September 4 are usually around February next year, when the cold air in the north has just moved south, causing the temperature in most parts of China to plummet, and it is even colder on September 9 and September 4.

In a word, the temperature is influenced by many factors, not only by sunshine duration, but also by geothermal and monsoon conditions. Under the influence of these comprehensive factors, the solstice in winter is not the coldest day of the year. But the coldest day of the year is three or nine days.