In "Counting Nine Songs", why is it said that "March 9th" is the coldest season?

Spread widely among our people? 99 cold songs? China people said: 1929, not to shoot, in 1949, take the ice road. You can see the cold season on March 9 from here.

Starting from our traditional solar terms, the twenty-four solar terms have entered the solstice since the winter of September. From winter to the future, although the solar altitude angle gradually increases, the heat lost every day is still greater than the heat received. Twenty days after winter, solstice? Three or nine days? The accumulated heat is the least, the temperature is the lowest, and the weather is getting colder. If there is the influence of cold air at this time, the weather will be even colder. And why is it nine, that is, nine days, and Sanjiu is the third? Nine days? In most parts of ancient China, especially in the north, because it was winter, and the people had poor cold-proof conditions and lacked cold-proof clothes, everyone hoped that winter would pass quickly, so they used it? Count to nine? I hope spring will come. Count nine days, and spring warms bloom. Therefore, March 9 is the coldest time during September 9.

Secondly, during March 9, the daytime is short, the illumination time is short, the angle between direct sunlight and the ground is small, and the intensity of ground sunshine per unit area is small. In addition, during March 9, we usually have a large area of snowfall, and the earth absorbs less heat during the day and emits more heat at night, so the daily heat budget on the ground is still in a deficit state, so we continue to lose heat and the ground temperature continues to drop. What is the deficit of the total heat balance on the ground? Sanjiu? This season has reached its climax. So it can also be seen from here that March 9 is the coldest season.

Finally, everything grows on the sun, and the alternation of cold and heat on the earth and many energy sources come from the sun. The temperature change on the earth is determined by the difference between the obtained solar radiation heat and the heat emitted from the surface. On the winter solstice, although the position of the sun moves northward to the limit, the daily heat received by the land is still less than the heat emitted, so the winter solstice is not the coldest day. With the decrease of solar radiation and the increase of surface heat dissipation, it is the coldest days of the year until the third day. It was not until March 9 that the daily heat absorbed by the land exceeded the daily heat lost, and the temperature gradually rose. That's why people feel this way. Sanjiu? This is the coldest day.