What clouds mean rain is coming?

Cirrostratus with a halo often precedes rain by a day. Altostratus suggests rain within hours, and nimbostratus is the steady-rain cloud itself.

What does SCT032 mean?

Scattered clouds — covering three to four eighths of the sky — with bases at 3,200 feet.

Cloud Types Explained: What Each Cloud Tells You

Clouds were the original forecast. The naming system is 200 years old, entirely logical, and still tells you what the atmosphere is doing before any app does.

Luke Howard's 1802 naming system uses four Latin roots that combine like Lego: cirro (high, wispy), alto (middle), strato (layered), cumulo (heaped), plus nimbo (raining). Cumulonimbus is a heaped raining cloud. Altostratus is a mid-level layer. Once you know the roots, most cloud names decode themselves.

High clouds, above 20,000 ft

Made of ice crystals, thin and often translucent.

Cirrus: wispy streaks, sometimes called mares' tails. Fair now, but often the leading edge of an approaching system 24 to 48 hours out.
Cirrostratus: a thin veil that produces halos around the sun or moon. Classic sign of a warm front approaching; rain often follows within a day.
Cirrocumulus: small ripples, the "mackerel sky." Unstable air aloft.

Middle clouds, 6,500 to 20,000 ft

Altostratus: a gray sheet that dims the sun to a watery disc. Steady rain is often a few hours away.
Altocumulus: patchy rolls or rounded masses. On a humid summer morning, altocumulus often means afternoon thunderstorms.

Low clouds, below 6,500 ft

Cumulus: the cotton-ball fair-weather cloud, formed by rising thermals. Harmless unless they start growing vertically.
Stratus: a featureless gray blanket. Drizzle, gloom, and fog that lifted.
Stratocumulus: lumpy low layer with breaks. Usually dry, often ahead of clearing.
Nimbostratus: thick, dark, continuous. This is the all-day rain cloud.

The vertical monster

Cumulonimbus spans all three levels, from a base near the ground to an anvil top at the stratosphere, sometimes 60,000 feet. It carries lightning, hail, downpours, and violent internal motion. A cumulus that keeps growing and hardening into a cauliflower shape is becoming one, usually within an hour.

THE PHOTOGRAPHER'S CLOUD REPORT

Scattered mid and high clouds are the best sunset ingredient, enough surface to catch color, enough gap to let light through underneath. A solid overcast kills a sunset by blocking the low sun entirely, and a completely clear sky produces a clean but flat one. Broken clouds with clear air on the western horizon is the setup worth driving for.

How coded reports describe them

Airport observations report clouds by coverage in eighths of the sky and by base height: FEW (1–2 eighths), SCT (3–4), BKN (5–7), OVC (8). So SCT032 means scattered clouds with bases at 3,200 feet. It's a precise version of what your eyes are already doing.