# Clouds Classification

- Link: https://www.weather.lk/clouds-classification/
- Published: 2026-08-19T13:14:57+05:30
- Author: WeatherLK

Clouds are an important part of the Earth’s weather system and can provide valuable
clues about changing atmospheric conditions. The modern classification of clouds
has its roots in the work of English pharmacist and meteorologist **Luke Howard**,
who observed that clouds often showed characteristics of more than one category.
His work helped establish the system used today, which recognizes ten basic cloud
types.

According to the World Meteorological Organization’s _International Cloud Atlas_,
these clouds are grouped according to their typical altitude: high-level, mid-level
and low-level clouds.

**High-Level Clouds**

High-level clouds include **cirrus (Ci), cirrocumulus (Cc), and cirrostratus (Cs)**.
They are generally thin and white and are mainly composed of ice crystals.

**Cirrus**

Clouds appear as delicate, detached filaments or narrow bands. Their hair-like or
silky appearance makes them easy to recognize. Because they consist of ice crystals,
they are usually transparent and do not greatly reduce sunlight. Around sunrise 
and sunset, cirrus clouds can take on striking yellow, orange or red colors.

![](https://www.cas.manchester.ac.uk/images/photos/Intro/300/cirrus_200.JPG)

**Cirrocumulus**

 Clouds form thin, white patches or layers arranged in small grains or ripples. 
They are mainly made of ice crystals and are often associated with cirrus or cirrostratus
clouds. These clouds are generally short-lived.

![](https://www.cas.manchester.ac.uk/images/photos/Intro/300/cirrocumulus_200.JPG)

**Cirrostratus**

Clouds form a transparent, whitish veil that can cover much of the sky. A distinctive
feature is the halo that is often visible around the Sun or Moon when light passes
through the ice crystals.

![](https://www.cas.manchester.ac.uk/images/photos/Intro/300/cirrostratus_200.JPG)

**Mid-Level Clouds**

The main mid-level clouds are **altocumulus (Ac), altostratus (As), and nimbostratus(
Ns)**. They are generally composed of water droplets, although ice crystals can 
occur at sufficiently low temperatures.

**Altocumulus**

 Clouds appear as white or gray patches, layers, rounded masses or rolls. They commonly
occur in several layers and may produce a colorful corona around the Sun or Moon.

![](https://www.cas.manchester.ac.uk/images/photos/Intro/300/altocumulus_150.JPG)

**Altostratus**

Clouds are gray or bluish sheets that partially or completely cover the sky. They
are thin enough for the Sun to appear through them, often with a dull, ground-glass
appearance. Light precipitation or virga may sometimes develop beneath them.

![](https://www.cas.manchester.ac.uk/images/photos/Intro/300/altostratus_150.JPG)

**Nimbostratus**

 Is a thick, dark gray cloud layer associated with prolonged rain or snow. It can
completely obscure the Sun, while low, ragged clouds may form underneath the cloud
base.

![](https://www.cas.manchester.ac.uk/images/photos/Intro/300/nimbostratus_200.JPG)

**Low-Level Clouds**

Low-level clouds include **cumulus (Cu), stratocumulus (Sc), stratus (St), and cumulonimbus(
Cb)**. Most are primarily composed of water droplets.

**Cumulus**

 Clouds have rounded, towering tops resembling cauliflower, with bright white upper
surfaces and darker, relatively flat bases. They commonly develop during the daytime
as warm air rises from the ground.

![](https://www.cas.manchester.ac.uk/images/photos/Intro/300/cumulus_200.JPG)

**Cumulonimbus**

 Is the major thunderstorm cloud. It can grow into a huge tower, with its upper 
section often spreading into a characteristic anvil shape. These clouds can produce
heavy rain, lightning, strong winds, hail and, in some situations, tornadoes.

![](https://www.cas.manchester.ac.uk/images/photos/Intro/300/cumulonimbus_200.JPG)

**Stratocumulus**

 Clouds form gray or whitish sheets, patches or rolls and often have a distinctive
honeycomb-like appearance. They are generally low and may cover large portions of
the sky.

![](https://www.cas.manchester.ac.uk/images/photos/Intro/300/stratocumulus_200.JPG)

**Stratus**

 Clouds form a uniform gray layer with a relatively even base. They may produce 
drizzle, snow grains or ice prisms when conditions are suitable. When stratus clouds
break apart, patches of blue sky often become visible.

![](https://www.cas.manchester.ac.uk/images/photos/Intro/300/stratus_200.JPG)

Understanding these ten basic cloud types helps meteorologists and weather observers
identify atmospheric conditions and recognize possible changes in weather. From 
delicate cirrus high above the Earth to powerful cumulonimbus thunderstorms, each
cloud type provides important information about what is happening in the atmosphere.