Tukuk-OSRead the Sky: 10 Cloud Types
Luke Howard classification 1803 · a modern field guide
Modern cloud classification was created by Luke Howard in 1803 — in Latin: cirrus (curled), cumulus (heaped), stratus (layered) and nimbus (rain). The ten genera we use today are still children of those four words. When our city pages show "Cloud cover 62%", that number is a blend of these genera detected by satellite plus model.
| Type | Shape & height | What it means for weather |
|---|---|---|
| Cirrus | high, feathery hair-thin cloud (6–13 km) | ice filaments; a sign the weather changes within 24–48 hours |
| Cirrocumulus | small high "mackerel scales" pattern | supercooled droplets; photogenic, sometimes a hint of afternoon storms |
| Cirrostratus | thin white veil, halo around moon/sun | the halo is light refracting through ice crystals; rain likely within 12–24 hours |
| Altocumulus | mid-level grey patches at 2–7 km | stable in the morning, can build into tropical afternoon storms |
| Altostratus | flat grey sheet over half the sky | a steady rain approaching; the sun shows through only dimly |
| Nimbostratus | dark thick layer at 1–4 km | steady rain or drizzle for hours; the best roof-cover cloud |
| Stratocumulus | low lumpy bands | the most common cloud type on Earth; rarely heavy rain |
| Stratus | low layer = fog at the ground | light drizzle, low visibility |
| Cumulus | puffy "fair weather" towers at 0.5–2 km | lovely in the morning; if they grow tall by late afternoon they are storm candidates |
| Cumulonimbus | storm tower 1–15 km with an anvil top (incus) | thunder, lightning, heavy rain, gust fronts and occasional hail |
The equatorial storm cycle
In Malaysia the daily cycle matters more than seasonal fronts: morning ground heating → cumulus swelling by midday → cumulonimbus thunderstorms between 4 and 7 pm → a clear night. That is why the "afternoon rain" forecast is almost always right on the Peninsula, and why we cache Kuching weather for only 45 minutes.
Cloud & astronomy
Stargazers know that cloud cover is the deciding factor: 0% plus a new moon = the best night. Check Tonight’s Sky for the moon phase, then the live cloud map to be sure your sky is really empty before carrying out the telescope.