What does it mean that clouds are a sign of the weather?

Clouds are a sign of the weather. Clouds will tell us what kind of change the weather wants. Everyone in our life has his own signboard. For example, if you want to get better or worse, you can use your face to remind others. If you are in a particularly bad mood, your face will be very bad. If you are in a particularly happy mood, your face will be filled with a smile.