Cumulus Humilis

Latin Translation

Cumulus = “heap” or “pile”

Humilis = “humble”

Height

Between 1200 feet to 6500 feet (~350 metres to ~2000 metres).

Small, fluffy clouds in an otherwise clear blue sky are usually cumulus humilis, or ‘fair weather cumulus’.

About

Also known as ‘fair weather cumulus’, these are the clouds you commonly see on a nice day. They are low altitude clouds, and appear small and fluffy, like sheep! They don’t grow very high into the atmosphere, have relatively flat bases and are generally all quite similar looking.

How do they form?

Air at the surface of the Earth is heated by incoming solar radiation (the sun), and as it does it lifts and cools. This water vapour condenses as it does so and a cloud is formed. This is why these clouds are often seen towards the afternoon, as the land needs to be warmed by solar heating. If conditions allow, these clouds can grow in height and size to form a cumulonimbus cloud.

What do we get from them?

Not a lot! They are generally present on fair weather days, or calm days. If they continue to grow during the day, they can form into larger cumulus clouds like a cumulonimbus, which can create showers or even thunderstorms.

How to spot them?

Look for small, fluffy clouds surrounded by blue sky. The base of the cloud should be reasonably flat, and the cloud itself should be grey to white.