Types of clouds

A cloud is a big fluffy thing made of water droplets, right? Well, yes, but there are around a dozen types of clouds, each with different characteristics. For example, a rain cloud can be a fluffy blob or a big sheet that extends across the sky, but a speckled cloud is made of ice and is too light to produce hailstones.

Scientists use different names to specify a cloud’s composition, altitude, and whether it’s likely to produce rain. Understanding these names can help you make informed decisions about the sky in your own animation.

Let’s look at some of these names and what they tells us about clouds. The full name of a cloud is made up of one or more category names.

Category by shape

Cumulus clouds are light, fluffy clouds with distinct outlines, commonly referred to as “fair weather” clouds. They’re dense and opaque, blocking out the sun as they move past it. Cumulus clouds can be very tall and thick, extending from low to high altitudes. They’re thick enough to cast shadows on themselves, making the clouds appear almost solid. The bottom of such a cloud can appear to be dark gray if the sun is above it.

Tall cumulus cloud

Stratus clouds are nearly uniform sheets of cloud material at medium or low altitudes. The sun appears through a thin stratus cloud as a hazy blob, but a thick stratus cloud can blot out the sun altogether. Fog is actually a stratus cloud at ground level, and the two often happen together.

Stratus cloud

Cirrus clouds are wispy high-altitude clouds that don’t block the sun to any great degree.

Cirrus clouds

Category by altitude

A cloud’s name can also tell you its altitude in the sky.

  • High (prefix: Cirro-): Above 23,000ft/7000m
  • Medium (prefix: Alto-): 6500–23,000ft/2000–7000m
  • Low: Below 6500ft/2000m

Rain category

Nimbus clouds are any clouds that produce precipitation (rain, snow, hail). Nimbus clouds have to get very heavy to start shedding water, so they’re found at the lower levels of the atmosphere.

Names of clouds

Scientists combine these categories to give us the names of many types of clouds. The name tells you about the cloud’s appearance, how high it is in the sky, and whether it’s likely to produce rain.

HighCirrusLong, wispy
HighCirrostratusTransparent sheet
HighCirrocumulusSpeckles of fluff
MediumAltostratusTranslucent sheet
MediumAltocumulusDotted fluff
LowStratusOpaque sheet
LowCumulusFluffy individual clouds
LowStratocumulusFluffy sheet
LowNimbostratusRain-producing sheet
LowCumulonimbusTall, anvil-shaped fluffy cloud that can produce rain, hailstones, lightning

What kinds of clouds are in your sky right now? Can you name them?

You can learn more about clouds in Chapter 7 of Physics for Animators.

Post Author: Michele Bousquet

Michele Bousquet is the author of Physics for Animators. A longtime animator, teacher, and writer, Michele has written more than 20 books on computer graphics. She holds a Bachelor's Degree in Mathematics and Computer Science from McGill University.