Cumulus Clouds: Low, Puffy, Fair-weather
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.
tFinally, 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 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
Cloud Color: White to gray
Precipitation Potential: Uncommon
Sky Cover: Mostly sunny to sunny
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.
Vertical, cauliflower outline
Ragged, broken up
Flattened, wider than it is tall
Medium height, tall as it is wide
Cumulus Cloud Varieties
Cumulus clouds have only one associated variety: radiatus.
Parallel bands and strips
Cumulus Cloud Supplementary Features
Cumulus clouds have five associated supplementary features: arcus, fluctus, praecipitatio, tuba, and virga. ⛅
Shelf cloud, gust collar
Kelvin-Helmholtz waves, curls
Precipitation reaching the surface
Funnel cloud, tornado
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. ⛅
Ragged frazzles, scud
Cap or hood over a cumuliform
Horizontal cloud veil
Waterfall condensation and spray
Pyrocumulus, caused from fire
Caused by human activity
Similar Cloud Types
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. Altocumulus
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. Stratocumulus
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.