1. Due to the impact of geographical position and landforms, the karst regions in Sichuan have very different climate.
In the east basin, the annual average temperature hits 14 to 19℃; the annual accumulated temperatures (all＞10℃) reach 4200℃—6100℃; the frost-free period lasts 280 to 300 days; the annual sunshine duration totals 900 to 1600 hours; the annual precipitation hits 900 to 1200mm.
In southwestern mountainous regions, the average temperature hits 15℃ to 20℃ in valleys or 5℃ to 15℃ in mountains; the annual accumulated temperatures (all＞10℃) reach above 4500℃ in the valleys to the south of Decang and sharply decline to 2000℃ in the area to the north of the same; the annual sunshine duration totals 1200 to 2700 hours; the annual precipitation reaches 800 to 1200mm; in 2008, freezing rain and snow disasters appeared in here.
2. Due to the impact of continental monsoon, the plateau region in northwestern Sichuan has a cold climate and a long winter, but no clear four seasons and almost no summer all the year around. The annual average temperature hits -2.5℃～6℃; in Serxu, Sêrtar, Hongyuan, Zoigê and other places, the absolute low temperature hits below -30℃; the annual accumulated temperatures (all＞10℃) usually go below 1000℃; for the fierce solar radiation and abundant sunlight, the annual sunshine duration exceeds 2400 hours; the annual precipitation hits 500～800mm, and more than 50% of the precipitation happens in the period from June to August; the annual evaporation capacity hits above 1000mm; the maintenance disastrous weathers include gale, hail, frost snow, sand storm, etc.; in the northwestern mountain and gorge region, the ravines have a low relief, and the climate is mild; the annual average temperature hits 11.5℃, the average temperature of January 1.5℃ and that of July 20℃; the frost-free period lasts 182 to 230 days; the annual precipitation reaches 500 to 600mm; in the river valley regions closed or semi-closed by the mountains in Wenchuan, Li County and Mao County and in the river valley regions in Derong, Batang, Xiangcheng County within the Jinsha River basin, because the annual precipitation only hits 500mm or so, the landscape is desertified or semi-desertified. It is one of the arid river valley regions in Sichuan.