An autumn rain and a cold show that autumn is the transition season from summer to winter, and autumn in Jianghuai area is often the area where cold and warm air masses meet. Whenever the cold air in the north goes south and meets the warm air mass in the Jianghuai area, it will bring an autumn rain and an autumn wind, which will cause the temperature to drop, and the temperature will be lower every time.
Extended data
The reason of one autumn rain and one cold
After the autumnal equinox solar terms, the sun gradually moved southward, and the heat from the sun in the northern hemisphere tended to decrease, with shorter days and longer nights. The heat radiated from the earth's surface to space, that is, the heat lost from the earth's surface, is increasing day by day, resulting in a gradual decrease in temperature. In the Arctic, the sun can hardly be seen during the day, but the night is long, so the temperature drops faster, which leads to the increasing influence of cold air.
Under the right conditions, cold air will invade the south. When the warm and humid airflow in the south meets the cold air in the north, it will produce rainy weather. At this time, after the war between warm air and cold air, it is often defeated and slowly retreats to the south. Then controlled by the cold air mass, the weather cleared up and the temperature dropped.
A few days later, when new cold air from Siberia or Mongolia moves south and meets the falling warm and humid air again over the region, new rainy weather will be formed. Of course, after the autumn rain, the warm air continued to decline, while the cold air became stronger as the sun moved south, and was controlled by the new and colder air mass, so the temperature was lower, so the phenomenon of "one autumn rain and one cold" appeared.
Baidu encyclopedia-an autumn rain, a cold autumn rain, a cold autumn rain
People's Network-Why "an autumn rain and a cold"