14 Types of Clouds Drifting Across the Sky (2025)

Clouds are more than just fluffy shapes in the sky; they tell us what’s happening in the atmosphere; Scientists classify different types of clouds based on their height, shape and whether they bring fair weather or severe weather.

Different types of clouds form when water vapor condenses into tiny water droplets or ice crystals, creating a visible mass in the sky. Some clouds develop vertically, reaching towering heights, while others spread across the entire sky in layered formations.

By observing clouds, we can predict rain or snow, changing temperatures and even storms before they arrive. Let’s explore some of the cloud types recognized by the World Meteorological Organization.

Contents

1. Cirrus Clouds
2. Cumulus Clouds
3. Stratus Clouds
4. Cumulonimbus Clouds
5. Altostratus Clouds
6. Altocumulus Clouds
7. Nimbostratus Clouds
8. Cirrostratus Clouds
9. Cirrocumulus Clouds
10. Stratocumulus Clouds
11. Cumulus Humilis
12. Cumulus Congestus
13. Shelf Clouds
14. Wall Cloud

Cirrus clouds are high-level clouds composed of ice crystals that form at high altitudes. They have a hair-like, wispy appearance and often indicate that a change in the weather is coming.

These delicate clouds can be seen near the sun or moon, sometimes producing a halo effect. They often form ahead of a warm front [source: UIUC].

Cumulus clouds are the classic "cotton balls" of the sky, often associated with fair weather. They have a brilliant white appearance with a rounded top and a uniform base. These clouds can grow vertically, sometimes developing into more intense cloud formations.

Stratus clouds cover the whole sky in a uniform gray layer, often bringing steady rain or light precipitation. These low clouds form when moist air rises gradually and spreads out in a sheet-like structure. When stratus clouds reach the Earth's surface, they create fog.

Cumulonimbus clouds develop vertically and are responsible for severe weather like thunderstorms, heavy rain, and even tornadoes. These towering giants extend through multiple atmospheric layers, sometimes reaching the level where jet aircraft fly.

Their dark, ominous appearance signals intense weather ahead and falling rain below.

Altostratus clouds are mid-level clouds that appear as large, grayish-blue sheets across the sky. They often precede a frontal system and signal that rain or snow is on the way. Unlike other clouds, they partially obscure the sun or moon but allow some light to filter through.

Altocumulus clouds appear as rounded masses or parallel bands in the middle level of the atmosphere. These middle clouds have a honeycomb appearance, with small spaces between the cloud formations. When seen in the morning, these layered clouds can indicate fair weather for the day.

Nimbostratus clouds are thick, dark clouds that cover the entire sky and bring continuous rain or snow. Unlike towering cumulus clouds, they lack vertical development and instead spread out as a dense, layered blanket.

Cirrostratus clouds are high-level clouds composed of ice crystals that create a thin, veiled layer across the sky. They often precede a change in weather and can produce halos around the sun or moon. Their appearance signals increasing moisture in the atmosphere.

Cirrocumulus clouds form at high altitudes and consist of small, white cloud patches. These clouds have a rippled or honeycomb appearance, often stretching across a large portion of the sky.

Unlike other high clouds, cirrocumulus clouds indicate fair weather with cold air moving in — unless you're in the tropics, when they could signal hurricane conditions!

Stratocumulus clouds are low clouds with a textured, bumpy appearance, often covering the entire sky in rounded clusters. They usually bring overcast conditions but do not produce heavy rain. These clouds can develop from cumulus clouds as they spread out.

Cumulus humilis clouds are small, fair-weather clouds that float lazily in the sky. They have a low vertical extent and do not grow into storm clouds. Their presence suggests stable atmospheric conditions with plenty of sun.

Cumulus congestus clouds develop vertically and are a sign that storms may be forming. These clouds are taller than cumulus humilis but have not yet reached the full intensity of cumulonimbus clouds. Their towering cumulus shape means they are full of rising moist air.

A shelf cloud is a wedge-shaped cloud that forms along the leading edge of a thunderstorm. These clouds often appear dark and ominous, stretching across the horizon ahead of severe weather. Shelf clouds indicate strong winds and rapidly changing atmospheric conditions.

A wall cloud is a low, rotating cloud base that extends downward from a severe thunderstorm. It forms when moist air is drawn into the storm’s updraft, creating a dark, menacing feature. Wall clouds can sometimes lead to tornado development.

We created this article in conjunction with AI technology, then made sure it was fact-checked and edited by a HowStuffWorks editor.