Why doesn't it snow in Sichuan?

Because of the low potential in the basin, cold air can't enter, but the water vapor in the basin is not easy to spread.

Sichuan basin belongs to the humid climate zone in the middle subtropical zone, with maritime climate characteristics. Due to the terrain barrier, the cold air is blocked in the northern Qinling Mountains, and the temperature in winter is higher than that in other areas at the same latitude.

The average temperature in Leng Yue is 3 ~ 5℃ in the north and 5 ~ 8℃ in the south, which is 1 ~ 4℃ higher than that in Shanghai, Hubei, Anhui and Guizhou in the south. The extreme minimum temperature in the north of the basin is -8 ~-5℃, and the extreme minimum temperature in the south is -5 ~-2℃.

Frost and snow are scarce, and the frost-free period is 280 ~ 350 days throughout the year. In winter, there is constant frost and snow in Wuhan at the same latitude, and Changning, whose basin is located in the Yangtze River basin, is frost-free all the year round.

Extended data

The temperature in the basin is high in the southeast and low in the northwest, with high bottom and low edge. The annual average temperature is 16 ~ 18℃. The active accumulated temperature above 10℃ is 4500 ~ 6000℃ and lasts for 8 ~ 9 months, belonging to the middle subtropical zone. The accumulated temperature in the southeast Yangtze River basin exceeds 6000℃, which is equivalent to the tropical climate of South Asia south of Nanling in China.

The temperature in the basin is high in the east and low in the west, high in the south and low in the north, high in the bottom and low in the edge, and the isotherm distribution is concentric. The temperature in the mountainous area on the edge of the basin has vertical distribution characteristics. The elevation of Emei Mountain and Jinfo Mountain rises by 100 m, and the temperature drops by 0.55℃ and 0.6 1℃ respectively. The average annual temperature at the top of Mount Emei is only 3℃, and the active accumulated temperature above 10℃ is 586℃, which is equivalent to cold temperate zone and sub-cold zone in climate.