There are four basic cloud classifications: cumulus, stratus, cirrus, and nimbus. Clouds are generally grouped according to height, as follows:
Name | Symbol | Description | Name | Symbol | Description | Name | Symbol | Description |
---|---|---|---|---|---|---|---|---|
Low Clouds | Middle Clouds | High Clouds | ||||||
Cumulus | ![]() |
Little vertical development; flattened | Altostratus | ![]() |
Thin, semi-transparent | Cirrus | ![]() |
Filaments ("mares tails") |
Cumulus | ![]() |
Considerable development; towering | Altostratus | ![]() |
Thick; may hide sun or moon | Cirrus | ![]() |
Dense, patchy |
Cumulonimbus | ![]() |
Tops lacking clear-cut outlines | Altocumulus | ![]() |
Thin, semi-transparent | Cirrus | ![]() |
Dense, anvil-shaped |
Stratocumulus | ![]() |
Spreading from cumulus | Altocumulus | ![]() |
Thin, patchy | Cirrus | ![]() |
Hook-shaped; thickening |
Stratocumulus | ![]() |
Not spreading from cumulus | Altocumulus | ![]() |
Bands; thickening | Cirrus and cirrostratus | ![]() |
Not reaching 45° altitude |
Stratus and/orfractostratus | ![]() |
Not bad weather | Altocumulus | ![]() |
Spreading from cumulus | Cirrus and cirrostratus | ![]() |
Exceeding 45° altitude |
Fractostratus/fractocumulus | ![]() |
Bad weather (scud) | Altocumulus | ![]() |
Double layered | Cirrostratus | ![]() |
Veil covering sky |
Cumulus andstratocumulus | ![]() |
Not spreading from cumulus | Altocumulus | ![]() |
Tufts or turrets | Cirrostratus | ![]() |
Not increasing; not covering entire sky |
Cumulonimbus | ![]() |
Clear top; often anvil-shaped | Altocumulus | ![]() |
Chaotic sky | Cirrocumulus | ![]() |
Main cirriform cloud |