Types of Clouds with Pictures

When we look up into the sky, we rarely analyse the types of clouds that we can see. However, there is a fascinating world of ‘cloud classification’, in which different clouds (defined as ‘water suspended in earth’s atmosphere’) are characterised according to their shape, height and location. There are over a hundred different types of clouds, but the list compiled below has reduced the multiple variations into the most common types of clouds using their distinctive features.

 

Before we begin, it is helpful to learn the meaning behind the Latin terms which

refer to their heights (altitude) in the atmosphere:

▷ Stratus / strato- = low (0 – 2000m)

▷ Alto- = middle level (2001m – 7000m)

▷ Cirrus / cirro- = high (7001m – 12000m)

 

 

The clouds below are arranged in order of the increasing heights at which they appear in the sky.

 

Cumulus

These are arguably the first clouds that most people think of when asked to picture a beautiful summer sky. They are white and fluffy, resembling the fleece of unshorn sheep. They are rounded at the top, but their bottoms are relatively flat.

‘Cumulus’ is the Latin word for ‘heap’, thus aptly describing the three-dimensional, vertical appearance of the cloud forms. They form on sunny days, often appearing in the late morning and disappearing towards late afternoon.

 

There are various iterations of this cloud according to their altitude; clouds which form on the lower levels of the atmosphere are called ‘stratocumulus’, while the clouds which form on the middle and upper levels of the atmosphere are called ‘altocumulus’ and ‘cirrocumulus’ respectively (more information on these below).

Stratus

 

These clouds are formless and uniform. They resemble a grey fog with no distinct boundaries, hanging low over the horizon.

They are seen on overcast days and can often signal an onset of cool mist or drizzle.

Stratocumulus

As mentioned above, they are low-hanging clouds which seem to have been formed from cumulus clouds being scattered across the sky, revealing patches of sky in between. They appear pale or dark grey when viewed from beneath and have less vertical height compared to cumulus clouds.

They form on cloudy days, often forming various clumps or wisps across the lower sky.

Cumulonimbus

 

These are some of the most vertically impressive clouds, spanning the lower, middle and upper regions of the atmosphere simultaneously. They have towering three-dimensional forms, often bearing resemblance to puffy mushrooms, or the smoke expelled from a volcano.

They can produce heavy rain or snow, hence their name, ‘thunderstorm clouds’.

 

Nimbostratus

 

These are the dark grey and ominous clouds which covers the entire sky in a thick layer, blocking out the sun. They span across both the lower and middle levels of the atmosphere.

They produce rain or snow and signal dark and gloomy days.

Altocumulus

 

These are the most common clouds in the middle layer of the atmosphere, forming various shapes and sizes across the sky. They can contain rippling elements, or appear and grey or white ‘fluffs’, ‘scales’, or ‘streaks’. They often form in a cluster or group, but due to their position higher in the sky compared to normal cumulus or stratocumulus clouds, they will appear smaller.

They often appear on warm or humid days, but may also signal storms or cooler temperatures later in the day.

Altostratus

 

Like the stratus clouds, they are greyish and indistinct in form. They span across the entirety of the mid-level sky in a uniform layer but are not thick enough to completely cover the sun from shining through.

They can often be found on warm, hazy days, but may also signal rain or snow approaching.

Cirrus

These are high level clouds, often appearing as white streaks or filaments, almost like lazy streaks of white paint across a blue canvas. Derived from the Latin word ‘cirrus’ meaning ‘a lock or tuft of hair’, they are wispy and thin. Due to their placement at higher altitudes where temperatures are much colder, they consist of ice crystals, rather than water droplets like the clouds above.

They appear most often in fair conditions but may also indicate storms or cyclones. However, it must be noted that these higher clouds (cirrus / cirro-) tend less to be associated with weather conditions, and do not signal any precipitation themselves.

 

Cirrostratus

As the name suggests, they are high-level, thin veils which forms across the sky in a near transparent layer. Although they may be difficult to discern, they form a ‘halo’, or ring of light, around the sun, due to the ice crystals in the upper layer refracting light. Like other cirrus clouds, they are made of ice-crystals.

Their presence indicates that there is a large amount of moisture in the upper levels of the atmosphere, and can sometimes signal the approach of a warm front and precipitation.

Cirrocumulus

 

These appear as white fluffs of clouds which are often arranged in rows. Due to their high altitudes, they appear much smaller than stratocumulus and altocumulus clouds, resembling the size of grains of rice.

They are relatively rarer than other types of clouds due to their momentary existence. They can be seen in cold but fair winter conditions.