Types of Clouds: How to Identify Them and What They Tell You
AnyWeather Editorial Team
Last updated: 2026-07-10
Based on public meteorological and environmental sources, plus AnyWeather data documentation.
Long before weather apps existed, people read the sky to plan their day. Clouds are still one of nature's most reliable short-term forecasts — once you know what to look for. This guide breaks down the main cloud types by altitude and shape, and explains what each one hints about the weather to come.
Clouds Are Grouped by Altitude
Meteorologists sort clouds into three height categories. Knowing the level is the fastest way to name a cloud you're looking at.
| Level | Typical Height | Main Cloud Types |
|---|---|---|
| High | 6,000–13,000 m | Cirrus, Cirrostratus, Cirrocumulus |
| Middle | 2,000–6,000 m | Altocumulus, Altostratus |
| Low | 0–2,000 m | Stratus, Stratocumulus, Cumulus, Nimbostratus |
The Clouds You'll See Most Often
Cirrus — thin, wispy streaks
High, feathery clouds made of ice crystals. On their own they usually mean fair weather, but if they thicken and spread, they can be the first sign that a warm front — and rain within a day or two — is on the way.
Cumulus — puffy "cotton ball" clouds
The classic fair-weather cloud: bright white, flat-bottomed, and scattered across a blue sky. They form on sunny days from rising warm air. Small cumulus mean settled weather, but if they grow tall and cauliflower-shaped through the afternoon, showers may follow.
Stratus — flat, grey blanket
A low, featureless layer that covers the whole sky like fog that never reached the ground. Stratus brings dull, overcast skies and sometimes light drizzle or mist.
Nimbostratus — thick rain cloud
A dark, heavy grey layer that blocks the sun. Nimbostratus is the cloud of steady, long-lasting rain or snow — the kind that settles in for hours.
Cumulonimbus — the thunderstorm tower
The giant of the sky. These towering clouds can reach the top of the troposphere and flatten into an "anvil" shape. They produce heavy rain, lightning, hail, and strong gusts. If you see one building overhead, it's time to head indoors.
Quick rule of thumb
Clouds getting lower and thicker usually means worsening weather. Clouds getting higher and thinner usually means conditions are improving.
How to Read the Sky in 30 Seconds
- Look at the height: High and wispy is usually fair; low and grey often means rain.
- Watch the trend: A sky filling in and darkening over a few hours signals an approaching front.
- Check the shape: Vertical, towering clouds mean strong updrafts and possible storms.
Source: World Meteorological Organization (International Cloud Atlas), National Weather Service.
Frequently Asked Questions
What are the main types of clouds?
The main types are cirrus (high, thin and wispy), cumulus (puffy, fair-weather clouds), stratus (low, flat grey layers), nimbostratus (thick rain clouds) and cumulonimbus (towering thunderstorm clouds). They are grouped into high, middle and low levels by altitude.
Which clouds mean rain is coming?
Nimbostratus brings steady, long-lasting rain, while cumulonimbus produces heavy showers, thunderstorms and hail. Thickening, lowering clouds — especially cirrus that spreads into a grey sheet — often signal rain within a day or two.
What do cirrus clouds mean?
Cirrus are thin, feathery ice-crystal clouds high in the sky. Alone they usually indicate fair weather, but if they thicken and spread across the sky they can be an early sign of an approaching warm front and rain.
How high are clouds?
Low clouds sit from the surface up to about 2,000 m, middle clouds from 2,000–6,000 m, and high clouds from about 6,000–13,000 m. Towering cumulonimbus can stretch through all three levels.
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