Clouds

Clouds come in many different types. Often the type of cloud can help us to understand what type of weather is moving in across an area.

Clouds are categorised according to height and shape. The different categories of clouds are then given names based on Latin words, e.g. nimbus clouds bring rain, stratus clouds appear as layers.

Example of cloud types and height above the ground.

The main clouds that you need to be aware of are:

Stratus: These are layered clouds that are low, grey and shapeless and usually are like a blanket of cloud over an area. They can bring some drizzle and rain.

Cumulus: These are clouds that move quite quickly. They are white and fluffy and look like cotton wool. They can bring rain showers – especially when the base is grey.

Cumulonimbus: These are much deeper clouds that climb high into the atmosphere. They often contain a lot of heavy rain and are associated with thunder and lightning storms.

Cirrus: These are very high clouds that are wispy and made up from ice crystals.

Cloud cover

Otka chart held up to the sky

Cloud cover is observed (not measured) in units called oktas. Each okta represents one eighth of the sky covered by cloud.