What makes it rain?

It is raining in the Central Plains (Yellow River Basin) of China. There is an agricultural proverb: the east wind rains and the west wind is sunny. You can also judge whether it will rain by looking at the direction of cloud drift: it will rain eastward without a trace; Clouds of West Horse stepping on the mud (II); Clouds go south, rain goes to the boat (below); Clouds go to the north to dry up the blank. You can also judge whether it will rain by observing the movements of animals and insects and natural scenes: swallows fly low in the snake gallery, ants move mountains and wear hats, water tanks sweat, and toads bark. These are all signs of rain.