Cumulus clouds belong to the Clouds with Vertical Growth group. They are puffy white or light gray clouds that look like floating cotton balls. Cumulus clouds have sharp outlines and a flat base. Cumulus clouds generally have a base height of 1000m and a width of 1km. Cumulus clouds can be associated with good or bad weather. Cumulus humilis clouds are associated with fair weather. Cumulus congestus clouds are usually associated with bad weather. Their tops look like cauliflower heads and mean that light to heavy showers can occur.

Cumulus cloud cells (the individual puffs of clouds) are about the size of your fist or larger when you hold up your hand at arm's length to look at the cloud.