Low clouds
(cloud base 0-2000m)
Cumulus
These are lumpy looking clouds that can mean drastically different types of weather. Caused by columns of warm air rising and cooling, small cotton wool-like clouds (cumulus humilis) are those of a fair weather day.
(cloud base 0-2000m)
Cumulus
These are lumpy looking clouds that can mean drastically different types of weather. Caused by columns of warm air rising and cooling, small cotton wool-like clouds (cumulus humilis) are those of a fair weather day.
Low clouds
(cloud base 0-2000m)
Cumulus Congestus
Cumulus clouds that stretch further up into the sky and have a crisp cauliflower appearance (cumulus congestus) are ones that can bring intense sudden showers.
(cloud base 0-2000m)
Cumulus Congestus
Cumulus clouds that stretch further up into the sky and have a crisp cauliflower appearance (cumulus congestus) are ones that can bring intense sudden showers.
Low clouds
(cloud base 0-2000m)
Stratus
These are low ragged looking clouds (grey or white-grey) in appearance. They often appear under rain clouds and can also be from the lifting and breaking up of fog. If thick enough they can produce drizzle or very light snow.
(cloud base 0-2000m)
Stratus
These are low ragged looking clouds (grey or white-grey) in appearance. They often appear under rain clouds and can also be from the lifting and breaking up of fog. If thick enough they can produce drizzle or very light snow.
Low clouds
(cloud base 0-2000m)
Stratuscumulus
This is a layer of clumpy-looking cloud that is either white or grey in appearance depending on how thick the cloud is. This sort of cloud can occur in any type of weather situation, but when thick enough light precipitation can result.
(cloud base 0-2000m)
Stratuscumulus
This is a layer of clumpy-looking cloud that is either white or grey in appearance depending on how thick the cloud is. This sort of cloud can occur in any type of weather situation, but when thick enough light precipitation can result.
Low clouds
(cloud base 0-2000m)
Cumulonimbus
These majestic looking clouds stretch far into the sky with the top of the clouds taking on an anvil appearance - this is caused by ice crystals at the top of the cloud. Under the cloud expect a very dark sky, torrential rain, heavy snow, hail and wind.
(cloud base 0-2000m)
Cumulonimbus
These majestic looking clouds stretch far into the sky with the top of the clouds taking on an anvil appearance - this is caused by ice crystals at the top of the cloud. Under the cloud expect a very dark sky, torrential rain, heavy snow, hail and wind.
Low clouds
(cloud base 0-2000m)
Cumulonimbus 2
Another variation of the same cloud type.
(cloud base 0-2000m)
Cumulonimbus 2
Another variation of the same cloud type.
Low clouds
(cloud base 0-2000m)
Mammatus
One other thing to look out for on the base of the cloud are strange udder shapes. These are mammatus clouds.
(cloud base 0-2000m)
Mammatus
One other thing to look out for on the base of the cloud are strange udder shapes. These are mammatus clouds.
Medium clouds
(cloud base 2000 - 6000m)
Nimbostratus
Unlike cumulonimbus clouds they are much more featureless, and the weather they produce isn't as severe. Expect long spells of moderate to heavy rain or snow linked to the presence of a weather front.
(cloud base 2000 - 6000m)
Nimbostratus
Unlike cumulonimbus clouds they are much more featureless, and the weather they produce isn't as severe. Expect long spells of moderate to heavy rain or snow linked to the presence of a weather front.
Medium clouds
(cloud base 2000 - 6000m)
Altostratus
Another cloud that can produce rain/snow. It often appears as a bland featureless layer of cloud either ahead of, or following the passage of a weather front. If thin enough, the sun appears as a bright disc through it.
(cloud base 2000 - 6000m)
Altostratus
Another cloud that can produce rain/snow. It often appears as a bland featureless layer of cloud either ahead of, or following the passage of a weather front. If thin enough, the sun appears as a bright disc through it.
Medium clouds
(cloud base 2000 - 6000m)
Altocumulus
Formed from either columns of rising air or from the break-up of altostratus clouds, these look like clumps of cloud spread out in a layer. Occasionally they'll produce those showers that are nothing more than a few big spots of rain.
(cloud base 2000 - 6000m)
Altocumulus
Formed from either columns of rising air or from the break-up of altostratus clouds, these look like clumps of cloud spread out in a layer. Occasionally they'll produce those showers that are nothing more than a few big spots of rain.
Medium clouds
(cloud base 2000 - 6000m)
Altocumulus Mackerel Sky
This formation of altocumulus cloud is often called a mackerel sky.
(cloud base 2000 - 6000m)
Altocumulus Mackerel Sky
This formation of altocumulus cloud is often called a mackerel sky.
Medium clouds
(cloud base 2000 - 6000m)
Altocumulus Lenticularis
Altocumulus clouds that appear like castle turrets (castellanus) can be a sign of thunderstorms, whilst those that look like UFOs (lenticularis) are caused by air 'bouncing' over hills.
(cloud base 2000 - 6000m)
Altocumulus Lenticularis
Altocumulus clouds that appear like castle turrets (castellanus) can be a sign of thunderstorms, whilst those that look like UFOs (lenticularis) are caused by air 'bouncing' over hills.
High clouds
(cloud base over 6000m)
Cirrus Uncinus Mare's Tails
Clouds made entirely out of ice crystals. They are white and wispy in appearance and produce no weather at the ground. Aircraft contrails (homogenitus) are a form of cirrus cloud.
(cloud base over 6000m)
Cirrus Uncinus Mare's Tails
Clouds made entirely out of ice crystals. They are white and wispy in appearance and produce no weather at the ground. Aircraft contrails (homogenitus) are a form of cirrus cloud.
High clouds
(cloud base over 6000m)
Cirrocumulus
Made up of ice crystals and droplets of super cooled water, these are the clumpier form of cirrus clouds. The clumps are very small and can almost give the sky the appearance of fish scales.
(cloud base over 6000m)
Cirrocumulus
Made up of ice crystals and droplets of super cooled water, these are the clumpier form of cirrus clouds. The clumps are very small and can almost give the sky the appearance of fish scales.
High clouds
(cloud base over 6000m)
Cirrocumulus 2
A dappled formation of cirrocumulus clouds.
(cloud base over 6000m)
Cirrocumulus 2
A dappled formation of cirrocumulus clouds.
High clouds
(cloud base over 6000m)
Cirrostratus
Quite often the first sign in the sky of an approaching weather front, this is a uniform layer of cirrus clouds. The sun is clearly visible through these clouds, but the presence of these clouds in front of the sun can cause optical effects such as a sun halo.
(cloud base over 6000m)
Cirrostratus
Quite often the first sign in the sky of an approaching weather front, this is a uniform layer of cirrus clouds. The sun is clearly visible through these clouds, but the presence of these clouds in front of the sun can cause optical effects such as a sun halo.
Hover over each of the cloud formations to access the information on the reverse.