Cumulus Clouds

Cumulus clouds are the big, puffy clouds you see on sunny days. They look like giant cotton balls floating in the sky. Cumulus means heap or pile in an old language called Latin. These clouds have flat bottoms and lumpy tops. They are some of the most fun clouds to watch because they often look like animals or shapes.

How Cumulus Clouds Form

Cumulus clouds form when warm air rises from the ground. As the air goes up, it cools off and the water in it turns into tiny drops. These drops group together to make a cloud. Because warm air keeps rising from below, the clouds grow upward into puffy shapes. That is why they look like stacks of fluff.

Fair Weather and Storms

Most cumulus clouds mean the weather is nice. They usually show up in the afternoon on sunny days. But sometimes cumulus clouds can grow very tall and turn into thunderstorm clouds. These are called cumulonimbus clouds. When that happens, they can bring heavy rain, lightning, and thunder. Small cumulus clouds are friendly, but big ones can be powerful.

Fun Facts

• A medium cumulus cloud can weigh more than a million pounds.
• People often see animal shapes in cumulus clouds.
• Cumulus clouds usually float about 3,000 to 6,000 feet above the ground.

Did You Know?

Even though cumulus clouds can weigh tons, they float because the tiny water drops are spread very far apart.