What do you mean by "clouds are like signs of the weather"?

Clouds are like the "signboard" of weather, which means that you can know the weather by looking at them.

"Signboard" is a sign hanging in front of a store, indicating the name or business variety of the store and used as a sign of the store. People can see the nature and business content of the shop at a glance from the signboard. The cloud has the same function. From people's long-term practical observation, what kind of weather will appear when they find out what clouds are hanging in the sky. Such as thin clouds in the sky, it is often a symbol of sunny weather; Those low and thick clouds are usually signs of rain and snow. In addition to the thickness and height of the cloud, its color and the time when these colors appear in the morning and evening will indicate some trend change of the weather. Therefore, you can "see the clouds and know the sky."