Why is it so hot in Sichuan?

There are significant differences in regional performance. The eastern part is warm in winter, early in spring, hot in summer, rainy in autumn, cloudy with little sunshine, long growing period, cold in winter in the west, almost no summer, abundant sunshine, concentrated precipitation and distinct wet and dry seasons. The vertical climate changes greatly and the climate types are diverse, which is conducive to the comprehensive development of agriculture, forestry and animal husbandry; There are many kinds of meteorological disasters with high frequency and wide range, mainly drought, and heavy rain, flood and low temperature often occur.

Due to the influence of geographical latitude and landform, the zonality and vertical direction of climate change obviously, and there is a great difference between the east and the west. Plateau mountain climate and subtropical monsoon climate coexist. According to the different water, heat and light conditions, it can be roughly divided into three climatic zones:

1. Subtropical humid climate zone of Sichuan Basin, namely Sichuan Basin and surrounding mountainous areas. This area is warm and humid all the year round, with annual average temperature 16 ~ 18℃, daily ≥ 10℃ for 240 ~ 280 days, accumulated temperature of 4000 ~ 6000℃, small daily temperature difference, large annual temperature difference, warm in winter and hot in summer, and frost-free period of 230 ~ 340. There are many clouds in the basin and few sunny days. The annual sunshine time is only 1000 ~ 1400 hours, which is 600 ~ 800 hours less than that in the lower reaches of the Yangtze River basin at the same latitude. Abundant rainfall, annual precipitation 1000 ~ 1200mm.

The second is the subtropical and semi-humid climate zone in southwest Sichuan. The annual temperature in this area is high, and the annual average temperature is 12 ~ 20℃. Annual amplitude is small, daily amplitude is large, and it is cold in the morning and warm in the afternoon. The four seasons are not obvious, but the dry and wet seasons are distinct. There is little precipitation. There are seven dry months throughout the year, and the annual precipitation is 900- 1200mm, of which 90% is concentrated in May-10. There are few clouds, many sunny days and long sunshine hours. The sunshine is 2000 ~ 2600 hours throughout the year. Influenced by foehn, the typical dry-hot valley climate is formed in the valley area, while the obvious three-dimensional climate is formed in the mountainous area.