Why are there the most rainy days in autumn in southwest China? And basically 10 it rains for seven or eight days?

This is a unique weather phenomenon in southwest China, and it is the autumn rain in West China.

Autumn rain in West China is a special weather phenomenon of rainy autumn in western China, which mainly occurs in Sichuan, Chongqing, Guizhou, Yunnan, eastern and southern Gansu, Guanzhong and southern Shaanxi, western Hunan and western Hubei. Among them, Sichuan basin, southwest Sichuan and western and northern Guizhou are the most common.

The autumn rain in West China usually occurs in September-165438+ 10, and the earliest date can sometimes start in late August and end at the latest 10.

The formation of autumn rain in West China is undoubtedly the result of the interaction between cold and warm air. After entering September every year, West China is in a low-pressure area between the subtropical high in the northwest Pacific and the Iranian high over 5,500 meters. The southwest airflow on the west or northwest side of the subtropical high in the northwest Pacific continuously transports warm and humid air from the South China Sea and the Indian Ocean to this area, which makes this area rich in water vapor conditions. At the same time, with the continuous eastward movement of cold air from the north side of the plateau or the reverse flow from the east to the west of China, cold and warm air frequently meet in the west of China, thus forming the autumn rain in the west of China.