How does rainfall differ between western and southeastern Gansu?

Precipitation in Gansu is generally meagre, with rainfall becoming increasingly less frequent as one moves farther inland toward the west.1

In the western part of the province, annual rainfall is very low, ranging from approximately 2 inches (50 mm) in Dunhuang to 3 inches (75 mm) in Jiuquan. Because of this aridity, agriculture in the region relies primarily on runoff from melting snow in the Qilian Mountains.12

In contrast, the southeastern part of the province is an exception to this pattern and receives relatively abundant rainfall. For example, in Pingliang, annual precipitation reaches 20 inches (500 mm). Across the province, summer is typically the period of maximum precipitation.1