Clouds form at many heights. In typical midlatitude classifications, low cloud bases often lie below about 6,500 feet, middle clouds commonly occupy roughly 6,500–20,000 feet, and high clouds appear above about 20,000 feet.
Cloud families by level
Low clouds include stratus and stratocumulus. Altocumulus and altostratus are midlevel examples; cirrus, cirrostratus and cirrocumulus are high-cloud types.
Why boundaries are approximate
Cloud-level heights vary with latitude, season and atmospheric conditions. Tropical high clouds can form at far greater heights than similar-looking clouds near the poles.
What about thunderstorms?
Cumulonimbus clouds can extend from a low base through multiple altitude bands, reaching high into the troposphere. Their vertical reach is why a single storm may contain rain, ice, lightning and strong updrafts.
Clouds above ordinary weather
Very high noctilucent clouds occur in the mesosphere around 80 kilometers above Earth—far above the typical tropospheric clouds used in everyday forecasts.
Frequently asked question
Are all clouds at the same altitude?
No. Cloud bases and tops differ greatly, sometimes even within the same weather system.
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