The Types of Clouds and What They Mean

Looking up at the sky you’ve probably noticed clouds. While clouds are similar in many ways, there are lots of different types and they form in different ways. Learn more about clouds and how they form on NASA Climate Kids.

Read the list below to learn about the different types of clouds, what they look like and where they appear in the sky. Or download and print out this chart (also available en Español)

High Altitude

• Cirrocumulus – High clouds with a puffy, patchy appearance and small spaces between clouds. Often form wave-like patterns.
• Cirrostratus – High clouds, light gray or white, often thin with the Sun or Moon seen through them. Usually cover much of the sky.
• Cirrus – High clouds, thin wispy and feathery, composed of ice crystals.

Middle Altitude

• Altocumulus – Middle clouds with a puffy, patchy appearance, usually with spaces between clouds.
• Altostratus – Middle clouds, light gray and uniform in appearance, generally covering most of the sky.

Low Altitude

• Nimbostratus – Low and middle dark gray clouds with precipitation falling from them. Bases are diffuse and difficult to determine because of falling precipitation.
• Cumulus – Low clouds. Clouds appear puffy and look like cotton balls, popcorn or cauliflower.
• Stratus – Low clouds, light or dark gray and generally uniform in appearance and covering most of the sky. Fog is a stratus cloud.
• Stratocumulus – Low clouds with irregular masses of clouds, rolling or puffy in appearance, sometimes with space between the clouds.
• Cumulonimbus – Large clouds with dark bases and tall billowing towers. Can have sharp well defined edges or an anvil shape at the top. Precipitation can obscure the base of the clouds. Clouds can be accompanied by thunder.

A dichotomous key is a tool scientists (and you!) can use to identify things in nature by answering yes or no questions. You can use this dichotomous key to identify types of clouds.

Go outside or look out the window toward the sky to begin observations. If you have a thermometer, measure the temperature and write it down. If you have a barometer, measure the air pressure and write it down.

Answer the questions on this dichotomous key to identify what types of clouds are in the sky. Make a note about what kinds of clouds you see.

You can help NASA scientists studying clouds! Just complete this Cloud Observations Report Form. If you need help, ask an adult to join you in your observations.

Then, upload the information you collected to the Globe Observer App using the Clouds tool. Your observations will help scientists confirm similar measurements made by satellites orbiting Earth.

Head over the NASA Space Place website to find out how to make this cloud mobile!