The ten different types of clouds

Clouds: they are critical to the earth's balance | Photo: Shutterstock

Clouds play an important role in the climate system and can warn us of what lies ahead. Learn how to identify cloud types.

Clouds provide shade, store water, and distribute heat from the equator to the poles. Their mechanisms are still not completely known, but their relevance to the earth's balance is unquestionable.

The World Meteorological Organization (WMO) created an International Cloud Atlas that recognizes ten types of cloud.

Clouds can appear at between 6,500 feet (1,981 meters) and 16,500 feet (5,029 meters).

The cloud names are the result of a combination of Latin prefixes and suffixes. Can you identify these clouds in your skies?

Cumulonimbus (Cb)

Huge cloud tower, sometimes with an anvil shape. Possible thunderstorm.

Cumulonimbus | Illustration: WMO


Cumulus (Cu)

Isolated, puffy cloud with sharp outlines.

Cumulus | Illustration: WMO


Stratus (St)

Grey-whitish low layer, sometimes with drizzle or snow grains. If Sun/Moon is visible, its outline is clear. It can occur in fragments.

Stratus | Illustration: WMO


Cirrostratus (Cs)

Transparent milky or fibrous veil; casts shadow, produces halo.

Cirrostratus | Illustration: WMO


Altostratus (As)

Smooth, extensive layer; casts no shadow, even if Sun/Moon is recognizable as a blurred dot.

Altostratus | Illustration: WMO


Nimbostratus (Ns)

Dark rain cloud or bright snow cloud. Usually continuous rain, snow, or ice pellets.

Nimbostratus | Illustration: WMO


Cirrus (Ci)

Hooks, feathers, bands, or patches with silky shimmer.

Cirrus | Illustration: WMO


Cirrocumulus (Cc)

Thin, pure white fields of small grains or ripples at a high level.

Cirrocumulus | Illustration: WMO


Altocumulus (Ac)

White/gray patches (turreted, lens-shaped, or balls of cotton), sheets, or structured layer with undulations or rolls.

Altocumulus | Illustration: WMO


Stratocumulus (Sc)

Grey or whitish fields, rolls or bundles, with rounded edges, at a low level; regularly arranged elements.

Stratocumulus | Illustration: WMO


Now, take a look at where low, middle, and high-level clouds begin to form:

Cloud levels: find out how high they begin to form | Illustration: Met Office

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