Cumulonimbus clouds: big and dark - a kind of nimbus cloud

Cumulonimbus clouds are a type of nimbus cloud

What is a nimbus cloud?

Nimbus clouds often mean that a thunder storm is brewing: there may soon be thunder and lightning. Get out of the swimming pool!

What causes thunderstorms?
Other kinds of clouds
More about weather

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?

Cumulonimbus and stratonimbus clouds

a thick blanket of cloud with rain falling out of it, and hills below it

A stratonimbus cloud

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.

More about rain
What’s a cumulus cloud?

And a stratonimbus cloud is a stratus cloud, a gray blanket cloud, with rain falling out of it. Or snow, if the weather is cold enough!

What’s a stratus cloud?

Nimbus clouds and the weather

Some parts of the world have nimbus clouds nearly every day, at least in the winter. The Chinook lived in a rainy place like that, in America’s northwest. Northern Europe is like that, too – northern France, and England, and northern Germany.

What causes the seasons?
Why does the wind blow?

In other places, like the Sahara Desert in northern Africa or the Kalahari Desert in southern Africa, it almost never rains or snows, so nimbus clouds – rain clouds – are rare. The American Southwest, where the Pueblo people lived, is another place where it hardly ever rains.