The World Meteorological Organization lists over 100 different types of clouds in its International Cloud Atlas. But, there are three or four main types of genera of clouds, which combine and form 10 basic cloud types. Here is an overview of the types of clouds, how to recognize them, and what kind of weather they produce.
- Cumulus clouds look like fluffy cotton balls. Low to the ground, they indicate fair weather, but when they tower into the sky they produce storms.
- Stratus clouds are sheets or layers of clouds. They can produce an overcast day or light rain or snow.
- Cirrus clouds are white wisps high in the sky.
- Nimbus clouds are either cumulus or stratus clouds that produce precipitation. Rain and snow clouds tend to be gray rather than white.
How Are Clouds Classified?
Clouds get classified according to the altitude at which they form, their upper height, and their shape. The names come from Latin words. Four common types are cumulus, stratus, nimbus, and cirrus. Alternatively, clouds get names from their height: high (cirrus or ciro-), middle (alto-), low (stratus, strato-), and multilevel (cumulus, cumulo-, nimbo-). In terms of shape, stratiform describes flattened sheets, cirriform describes wisps or patches, and cumuliform clouds are masses or heaps. Nimbus clouds are ones that produce precipitations.
Types of Clouds
Cumulus Clouds
Cumulus clouds are the puffy popcorn shapes you produce when asked to draw clouds. They are puffy with rounded tops. Cumulus clouds appear white when well-lit, but have flattened, darker bases.
You’ll see cumulus clouds form on clear, sunny days as the ground heats up. They often appear mid-morning, develop, and vanish as the sun sets. They indicate the presence of moisture in the air, but don’t necessarily produce rain or snow.
Stratus Clouds
Stratus clouds are flat, uniform, gray clouds. Usually, they are gray and resemble fog near the horizon, rather than actual fog which is on the ground.
Stratus clouds produce overcast days. Sometimes they produce mist or a light drizzle. Altostratus (and altocumulus) clouds sometimes produce virga, which is precipitation that evaporates before it reaches the ground.
Nimbus Clouds
Nimbus clouds produce precipitation in the form of rain, hail, or snow. Both cumulus and stratus clouds can be nimbus clouds, which go by the names cumulonimbus and stratonimbus.
Cumulonimbus clouds are thunderheads that tower from the troposphere into the stratosphere. The cloud top often flattens into an anvil shape. The cloud’s bottom is dark.
Nimbostratus clouds are less ominous. They are gray, multi-level clouds that yield the occasional rain shower or snow flurry.
Cirrus Clouds
Cirrus clouds are patchy or wispy white clouds high in the atmosphere. Because of their altitude, these clouds consist of ice crystals rather than water vapor.
Combining Cloud Names
Some clouds have multiple features and have combination names.
- Cirrostratus: Cirrostratus clouds are thin veils high in the atmosphere.
- Cirrocumulus: Cirrocumulus clouds appears a high white ripples, scales, or stripes.
- Altostratus: Altostratus clouds are either opaque or translucent gray clouds at intermediate altitudes.
- Altocumulus: Altocumulus clouds are irregular patches or waves of mid-level clouds.
- Stratocumulus: Stratocumulus clouds are low-level irregular gray patches or sheets.
Types of Clouds Worksheet
Practice identifying the types of clouds based on their appearance.
[Google Apps worksheet][worksheet PDF][worksheet PNG][answers PNG]
| Altitude | Cloud Type | Symbol | Features |
|---|---|---|---|
| Extremely high | Polar mesospheric clouds or noctilucent veils | PMC | Night-shining clouds |
| Very high | Nitric acid and water polar stratospheric clouds | PSC | Iridescent, most visible at twilight |
| High | Cirrostratus Cirrus Cirrocumulus | Cs Ci Cc | Thin veil Delicate wisps Pure white rounded masses or ripples |
| Mid | Altostratus Altocumulus | As Ac | Opaque or translucent gray clouds Irregular patches or sheets in groups or waves |
| Low | Stratus Stratocumulus Cumulus | St Sc Cu | Flat or ragged clouds resembling fog Irregular patches or sheets shading to gray Detached clouds with flat bases and tops |
| Multi-level | Nimbostratus | Ns | Dark gray multi-layers that appear lit from within that produce precipitation |
| Towering vertical | Cumulonimbus | Cb | Heavy, towering cloud with dark base and very high top that produces lightning, thunderstorms, snow showers, hail |
| Surface | fog or mist |
Other Types of Clouds
Other noteworthy types of clouds are lenticular clouds and mammatus clouds.
Lenticular clouds (Lenticularis or len) are lens-shaped or almond-shaped stationary clouds. They are a specific form of stratocumulus, altocumulus, or cirrocumulus clouds. These clouds form around mountains, hills, and buildings and resemble UFOs.
Mammatus clouds are cumulus clouds (usually cumulonimbus) with cellular pouches hanging from the cloud base. Clouds with “lumpy” undersides and anvil shapes are associated with extreme turbulence and severe thunderstorms.
References
- Ackerman, Steven A. (2011). Meteorology: Clouds and the Greenhouse Effect. Jones & Bartlett. ISBN 978-0-7637-8927-5.
- Burroughs, William James; Crowder, Bob (2007). Weather. San Francisco: Fog City Press. ISBN 978-1-74089-579-8.
- Miyazaki, R.; Yoshida, S.; Dobashi, Y.; Nishita, T. (2001). “A method for modeling clouds based on atmospheric fluid dynamics”. Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics. doi:10.1109/PCCGA.2001.962893. ISBN 978-0-7695-1227-3.
- World Meteorological Organization, ed. (1975). International Cloud Atlas. Vol. I. ISBN 978-92-63-10407-6.