The ten main cloud types
The ten genera of the WMO International Cloud Atlas. Heights are for the middle latitudes: clouds sit lower near the poles and higher in the tropics. Nimbostratus is a middle cloud that usually spreads into the levels above and below; cumulus and cumulonimbus have low bases but can tower into the middle and high levels. Some weather services draw the lines a little differently (Australia's Bureau of Meteorology uses about 2.5 km and 6 km).
Every cloud in the sky belongs to one of ten families, and their names are built from just four Latin words. Learn the ten and a glance upward tells you something about the weather on the way.
Build from the parts first: cirrus (curl of hair, high and icy), cumulus (heap), stratus (spread out, a layer) and nimbus (rain cloud), plus alto for the middle level. Then each name is a small sum you can work out, which is far easier than ten separate facts. Chunk by level (three high, three middle, four low), and pair each name with a quick sketch: picture plus words is dual coding. Best of all, step outside and name the clouds you see.
Encode make it vivid → Space bring it back on day 1, 3, 7, 21 → Retrieve pull it from your head. From the infographic Remember It on Purpose.
The ten main cloud types
| Cloud | Symbol | Level | Usual base height | What it looks like |
|---|---|---|---|---|
| Cirrus | Ci | High | About 5-13 km (16,500-45,000 ft) | Thin white wisps, strands or hooks of ice crystals, like brush strokes across the sky. |
| Cirrocumulus | Cc | High | About 5-13 km (16,500-45,000 ft) | Tiny white grains or ripples in rows, with no shading; each bit looks smaller than your little finger held at arm's length. |
| Cirrostratus | Cs | High | About 5-13 km (16,500-45,000 ft) | A thin, milky veil over much of the sky that often makes a ring of light (a halo) around the Sun or Moon. |
| Altocumulus | Ac | Middle | About 2-7 km (6,500-23,000 ft) | White or gray patches, rolls or rows with some shading; each piece about one to three fingers wide at arm's length. |
| Altostratus | As | Middle | About 2-7 km (6,500-23,000 ft) | A gray or bluish sheet; the Sun shows dimly, as if through frosted glass, with no halo. |
| Nimbostratus | Ns | Middle | About 2-7 km (6,500-23,000 ft) | A thick, dark gray layer that hides the Sun and brings steady rain or snow. |
| Stratocumulus | Sc | Low | Surface to about 2 km (6,500 ft) | Low gray or white lumps and rolls with darker parts, each wider than three fingers at arm's length, often with gaps of blue. |
| Stratus | St | Low | Surface to about 2 km (6,500 ft) | A flat, even gray layer, like fog that has lifted off the ground; it may bring drizzle. |
| Cumulus | Cu | Low | Surface to about 2 km (6,500 ft) | Puffy, separate heaps with flat bases and bright, rounded tops, like cotton balls or cauliflower. |
| Cumulonimbus | Cb | Low | Surface to about 2 km (6,500 ft) | A huge, towering storm cloud, often with a flat anvil-shaped top, bringing thunder, lightning, heavy showers and sometimes hail. |
Build from the parts first: cirrus (curl of hair, high and icy), cumulus (heap), stratus (spread out, a layer) and nimbus (rain cloud), plus alto for the middle level. Then each name is a small sum you can work out, which is far easier than ten separate facts. Chunk by level (three high, three middle, four low), and pair each name with a quick sketch: picture plus words is dual coding. Best of all, step outside and name the clouds you see. · teddyrookbook.com/memory/challenges/cloud-types/
Sources
- WMO International Cloud Atlas: levels (étages) and approximate heights
- WMO International Cloud Atlas: Altocumulus (definition)
- WMO International Cloud Atlas: useful concepts (genera and abbreviations)
- Hong Kong Observatory: The classification and nomenclature of clouds
- Australian Bureau of Meteorology: Cloud types
Checked October 30, 2026. Progress is kept on this device only (per learner). More lists: all memory challenges · memory games.