When does the sandstorm weather in Gansu usually start?

Sandstorm weather usually occurs in spring.

Usually from February to May. The specific occurrence is related to the precipitation (rain and snow) in that year, and the annual occurrence time, frequency and intensity are not consistent. Basically, there are many Hexi areas, but there are few Lanzhou, Baiyin, Pingliang and Qingyang, and there are few other cities in the province.