Why are some clouds gray?

May 31, 2008 5:20:21 AM PDT
There's two different weather phenomena that can make clouds look gray instead of white. Both times, though, it's due to a lack of sunlight penetrating the cloud.

Erica's Answer:

First off, a cloud can look gray if the sun is low in the sky, such as at sunrise or sunset. Another reason for gray clouds is if the cloud has a very high concentration of water droplets in it. Both of these instances limit the amount of sunlight that can pass through the entire cloud.

- Erica