What are the coldest days of the year?

Generally speaking, it is from March 9 to April 9, and the winter solstice is usually on June 265438+February 2 1 to the 23rd, while March 9 and April 9 are about winter to the future 18 to 27 days, that is, from the beginning of 1 month to the end of 1 month every year.

At this time, the coldest weather is mainly caused by the daily heat budget deficit on the ground, and friends with geographical knowledge should know that the ground in the northern hemisphere receives the smallest direct sunlight area from winter to day, and the solar heat obtained at this time is also the least.

With the passage of time, the ground temperature continued to drop, and by 3949, the budget deficit of ground heat in the northern hemisphere reached the maximum. Coupled with the influence of the Siberian cold current, it naturally became the coldest time of the year.

The origin of the number nine

"Count nine" means that every nine days from winter to Sunday, it will be 19, and then it will be 29 every nine days, and so on until the end of the winter of 1999. I often hear the old man say, "Don't shoot in 1929, walk on the ice in 3949, watch the willows along the river in 5969, open the river in 79, attract geese in 89 and bloom in 90!" That's what it means.

From here, we can also see the wisdom of the ancient working people, because it is very difficult to keep warm in ancient winter, and winter is very difficult for ordinary people. In order to make their lives look forward to, ordinary people will use "nine" to calculate their days, because "nine" is a big number in people's minds. After 998 1 day, winter will be over.