There's more to these white, fluffy formations than meets the eye!


1 A cloud droplet is just 0.02mm in diameter – that’s five times smaller than the thickness of a piece of paper – yet these droplets condense together to form clouds up to 14 miles high!

2 High-level clouds start at 20,000ft and are made up of ice crystals – whereas clouds lower down are made up of water droplets.

3 Arcus clouds look a little like a tidal wave in the sky, and are also known as shelf and roll clouds. They’re often spotted beneath powerful storms, and form when warm air from the ground is pushed up by the cold air exiting from the storm cloud in the downdraft. These spinning cylinders herald the coming of the storm front.

Arcus cloud


4 Cirrostratus are high-level clouds that cover large areas of sky, and can stretch for thousands of miles.

5 Venus has clouds made up of sulfur dioxide and sulphuric acid – Saturn and Jupiter have ammonia clouds.

6 ‘Cloud suck’ is a phenomenon known to hang-gliders and paragliders. Pilots get ‘sucked’ up to significant heights due to the formation of a thermal beneath the base of cumulus clouds.

In 2007, paraglider Ewa Wisnierska-Cieslewicz had the misfortune to experience this effect when she was sucked up to a staggering 32,600ft (passenger jets cruise at 30-40,000ft) ascending at 66ft per second. Losing conscious due to lack of oxygen and in temperatures of -56C, she came to after an hour and landed, covered in ice, after a three-and-a-half hour flight.

7 Flying into a cumulonimbus cloud – heavy, dense clouds that reach up to 14 miles high – is extremely dangerous, and pilots avoid them at all costs. They’re associated with extreme weather, such as torrential downpours, hail storms, lightning and tornados.

Cumulonimbus cloud


8 Cloud seeding is a technique that induces rain from a cloud by ‘seeding’ the cloud with silver iodide or dry ice from a plane. This encourages the water droplets within the cloud to condense and fall as rain.

9 Noctilucent, or night clouds, are very rare – and are seen at immense heights above the Earth at up to 40 miles from the ground. They’re called night clouds as they only become visible as the first of the stars appear. These formations look like silvery blue, or sometimes orangey red, wispy streaks across the sky.

10 Some believe certain UFO sightings could in fact be lenticular clouds. These form in hilly or mountainous regions when air containing enough moisture blows over the mountains and condenses to create a wave-like formation.

Lenticular cloud


11 Fluffy-looking cumulus clouds are the basis of the cloud icon used on the BBC’s weather forecasts.

12 Clouds are lucky in Iran. To tell someone they are blessed, you would say, ‘Your sky is always filled with clouds.’