Nimbus clouds often mean that a thunder storm is brewing: there may soon be thunder and lightning. Get out of the swimming pool! Nimbus is a fancy word, but it really just means a cloud that already has rain or snow falling out of it. Can you see the rain falling in the picture to the right?
Clouds don’t have to be just one kind of cloud – they can be more than one type at the same time. So you often see the names of clouds combined: a cumulonimbus cloud is a cumulus cloud, a puffy thick cloud, with rain falling out of it, and a stratonimbus cloud is a stratuscloud, a gray blanket cloud, with rain falling out of it.
Learn by doing: a project with clouds
More about cumulus clouds
More about cirrus clouds
And more about clouds