What is a description of a Cumulus cloud?

Answer 1

Fluffy clouds. They form low in the sky and can bring short, heavy showers. (Some grow into tall dark clouds that cause heavy percipition, e.g rain)

Answer 2

Cumulus clouds are fluffy, white clouds with a rounded shape and flat base. They usually signal fair weather, but can also develop into larger storm clouds if conditions are right. Cumulus clouds are formed by the vertical convection of warm air rising and cooling in the atmosphere.