Why does Hubei and Hunan feel coldest in winter?

Hunan and Hubei "two lakes and plains" are connected as a whole, with Wushan and Xuefeng Mountain in the west, Dabie Mountain in Hubei and Anhui and Mufu Mountain in Jiangxi in the east. The cold air in the north is sandwiched by the mountains on the east and west sides, and it goes south along the wide passage of the two lakes and plains, and the temperature drops much faster than that in Guizhou, Jiangxi and other provinces on both sides.

Hunan has a continental subtropical monsoon humid climate with three characteristics:

First, light, heat and water resources are abundant, and the high values are basically synchronized.

Second, the climate changes greatly in a year. It is hot in Leng Xia in winter, changeable in spring, sudden drop in autumn, rainy in spring and summer, and drought in autumn and winter. The climate changes greatly from year to year.

Third, the most obvious vertical climate change zone is the mountainous area surrounded by mountains on three sides. Especially in the mountainous area of southern Hunan. ?

Thermal conditions in Hunan

The average annual temperature in Hunan is generally 16 ~ 19℃. In winter (65438+ 10), the average temperature in Leng Yue is above 4℃, and the average number of days when the average annual daily temperature is below 0℃ is less than 10. The average temperature in spring and autumn is mostly between 16 ~ 19℃, and the temperature in autumn is slightly higher than that in spring. The average temperature in summer is mostly between 26℃ and 29℃, and it can be as high as 30℃ in Hengyang area.

Hunan is rich in heat, and the average daily temperature in most areas ranges from 5600℃ to 6800℃ through the active accumulated temperature above 0℃. The active accumulated temperature above 10℃ is 5000 ~ 5840℃ and can last for 238 ~ 256 days. The active accumulated temperature above 15℃ is 4 100 ~ 5 100℃, and it can last 180 ~ 208 days; The frost-free period is 253 ~ 3 1 1 day.

Hunan's heat conditions are second only to Hainan, Guangdong, Guangxi and Fujian, close to Jiangxi and better than other provinces.