Why do rain clouds look GRAY and others look WHITE if they're all just WATER?

Question

Why do rain clouds look GRAY and others look WHITE if they're all just WATER?

Answer 1

The color of the cloud is directly related to how much water vapor the cloud is made up of.  The more water in the cloud the darker the color.  When the clouds become dark grey, expect rain.

Answer 2

Its all in the cloud level and the amount of moisture. Since clouds that produce rain tend to be at a lower atmospheric height above the earth's surface, and since they are thicker, they block out the suns rays more effectively than a fair weather cloud, and that is why rain clouds look gray, but they really aren't. If you ever have the chance to see a thunderhead from a distance, the bottom will look gray, but if you look at the top where the sun can shine on the clouds, you will see that is actually white, not gray.