Cumulus Clouds: Low, Puffy, Fair-weather

  1. WhatsThisCloud
  2. Cloud Types
  3. Cumulus Clouds

Definition: Low-altitude, fluffy heaps of clouds with cotton-like appearance

Description & Characteristics. Cumulus clouds are the clouds that we all drew as kids. They’re cotton ball clouds, popcorn clouds, and the clouds in the opening scene of The Simpsons. Though they come in different shapes and sizes, they’re generally the easiest type of cloud to pick out of the ten different cloud types. When the average person is asked to visualize a cloud, cumulus clouds are generally the first to come to mind.

The different sizes of cumulus clouds are described by their four associated species. If the cumulus cloud you’re looking at is wider than it is tall, then it’s a cumulus humilis. If it’s as wide as it is tall, then it’s a cumulus mediocris. But when a cumulus cloud is taller than it is wide, known as cumulus congestus, things can get… interesting. If cumulus congestus clouds continue their vertical growth, they’re capable of producing rain, and can eventually morph into a cumulonimbus cloud, or thunderstorm.

If its vertical growth is impressive enough, you might find a cap cloud on top of a cumulus cloud, otherwise known as a pileus cloud. While cumulus clouds are known as low level clouds, cumulus congestus clouds with more extensive vertical growth can rise into the middle level.

Finally, if you see a cumulus cloud that’s ragged and broken up, consider it of the species cumulus fractus. You might witness these clouds in the evening as cumulus clouds begin to dissipate, or perhaps on a windy day.

Cumulus (Cu)
Cumulus fractus (Cu fra)
Cumulus congestus virga (Cu con vir)
Cumulus mediocris (Cu med)
Cumulus humilis (Cu hum)
Cumulus (Cu)
Cumulus congestus (Cu con)
A photograph of cumulus clouds (Cu) over Everglades National Park in Florida

Cumulus Cloud Facts

  • Cloud Level (Étage): ….. Low, but capable of extending into higher levels (congestus)
  • Altitude/Height: ……… 0.2-2km (2,000-7,000 ft)
  • Latin Term: …………… Derives from cumulo-, meaning heap
  • Abbreviation: ………… Cumulus can be abbreviated as Cu
A bar graph showing the visual color of a cumulus cloud

Cloud Color

White to gray

A bar graph showing the precipitation potential of a cumulus cloud

Precipitation Potential


A bar graph showing the amount of sky cover from a cumulus cloud

Sky Cover

Mostly sunny to sunny

A bar graph showing how common observing a cumulus cloud might be

Cloud Frequency

Very common

Cumulus Cloud Species

Cumulus clouds have four associated cloud species: congestus, fractus, humilis, and mediocris. The species congestus, humilis, and mediocris are unique to cumulus clouds.

A graphical illustration of a cumulus congestus cloud

Cumulus congestus

Vertical, cauliflower outline

A graphical illustration of a cumulus fractus cloud

Cumulus fractus

Ragged, broken up

A graphical illustration of a cumulus humilis cloud

Cumulus humilis

Flattened, wider than it is tall

A graphical illustration of a cumulus mediocris cloud

Cumulus mediocris

Medium height, tall as it is wide

Cumulus Cloud Varieties

Cumulus clouds have only one associated variety: radiatus.

A graphical illustration of a cumulus radiatus cloud

Cumulus radiatus

Parallel bands and strips

Cumulus Cloud Supplementary Features

Cumulus clouds have five associated supplementary features: arcus, fluctus, praecipitatio, tuba, and virga.

A graphical illustration of a cumulus arcus cloud

Cumulus arcus

Shelf cloud, gust collar

A graphical illustration of a cumulus fluctus cloud

Cumulus fluctus

Kelvin-Helmholtz waves, curls

A graphical illustration of a cumulus praecipitatio cloud

Cumulus praecipitatio

Precipitation reaching the surface

A graphical illustration of a cumulus tuba cloud

Cumulus tuba

Funnel cloud, tornado

A graphical illustration of a cumulus virga cloud

Cumulus virga

Evaporating rain strips

Cumulus Cloud Accessories & Other Clouds

Cumulus clouds have three associated accessory clouds: pannus, pileus, and velum. They also have three other clouds associated with the cloud type: cataractagenitus, flammagenitus and homogenitus.

A graphical illustration of a cumulus pannus cloud

Cumulus pannus

Ragged frazzles, scud

A graphical illustration of a cumulus pileus cloud

Cumulus pileus

Cap or hood over a cumuliform

A graphical illustration of a cumulus velum cloud

Cumulus velum

Horizontal cloud veil

A graphical illustration of a cumulus cataractagenitus cloud

Cumulus cataractagenitus

Waterfall condensation and spray

A graphical illustration of a cumulus flammagenitus cloud

Cumulus flammagenitus

Pyrocumulus, caused from fire

A graphical illustration of a cumulus homogenitus cloud

Cumulus homogenitus

Caused by human activity

Similar Cloud Types

Cumulus vs. Altocumulus

Altocumulus clouds are generally seen as patches of clouds grouped together, either in rolls, sheets or heaps. Cumulus clouds are more often seen as individual clouds. Cumulus clouds are also much closer to the ground. A key reminder trying to determine the difference between cumulus and altocumulus clouds are that the two cloud types don’t have any shared cloud species.

Cumulus vs. Stratocumulus

Both cumulus and stratocumulus clouds are found at the same height, but stratocumulus clouds are more of a layer cloud than a cumulus cloud, usually found in conjoined groups or clumps of clouds. Additionally, stratocumulus clouds are generally darker than cumulus clouds. It’s also important to note that both clouds don’t share any cloud species or varieties besides the radiatus cloud variety.

Cumulus vs. Cumulonimbus

Cumulonimbus clouds fully developed are much different than your typical fair-weather cumulus cloud, but a cumulus congestus cloud is the precursor to a cumulonimbus cloud. If you’re trying to decide between the two, and the cloud in question has precipitation, lightning, or a fibrous upper portion, you can consider it a cumulonimbus cloud. Otherwise, you can peg it as a cumulus cloud.