Main climatic boundary map of China.

1. 1℃ 10 monthly isotherm (which is also the dividing line between subtropical zone, warm temperate zone and plateau climate zone): roughly along the southeast edge of the Qinghai-Tibet Plateau, passing through Qin to the east.

Linghuaihe line.

2.800 mm isoprecipitation line (dividing line between humid area and semi-humid area): along the southeast edge of Qinghai-Tibet Plateau, it crosses the Qinling-Huaihe line eastward.

3.400 mm isoprecipitation line (dividing line between semi-humid area and semi-arid area): from the western slope of Daxing 'anling to the eastern Himalayas via Zhangjiakou, Lanzhou and Lhasa.

4.200mm isoprecipitation line (the dividing line between semi-arid area and arid area): it passes through Yinshan Mountain, Helan Mountain, Qilian Mountain and Bayankala Mountain to Gangdise Mountain.

5. The dividing line between the humid area and the arid area, that is, the dividing line with an average annual precipitation of 400 mm ... from the western foot of Daxinganling-Yanshan-Daqingshan-Liupanshan-Bayan Kara-Tanggula Mountain-Nyainqentanglha Mountain. The east of this dividing line is rich in precipitation and is a humid area; To the west of this dividing line, except for Tianshan Mountain, Qilian Mountain, Altai Mountain and other mountainous areas, the precipitation is slightly higher, and other areas are relatively dry.

6. The dividing line between monsoon climate zone and non-monsoon climate zone: from Daxinganling-Yinshan-Helan Mountain-Bayankara Mountain Range-Gangdise Mountain Range. East of this dividing line is the monsoon region. The monsoon region is controlled by high-pressure system in winter, prevailing northerly wind, dry and cold climate, and controlled by low-pressure system in summer, prevailing southerly wind and humid climate. The west of this dividing line is a non-monsoon area with a dry climate.