How Clouds Form and Why It Rains
The sky above us is constantly changing. See how clouds form and what decides whether it will rain.
From water vapour to a cloud
Warm air rises and cools down. The water vapour it contains condenses into tiny droplets or ice crystals, which together form a cloud.
Three basic cloud types
- Cumulus – white, heap-shaped clouds associated with fine weather
- Stratus – a continuous grey layer, typical of overcast days
- Cirrus – high, wispy clouds made of ice crystals
When it starts to rain
When droplets in a cloud merge into big enough drops, gravity pulls them down as rain. The darker and more massive the cloud, the more water it carries.
Next time you watch the sky, try to guess from the shape of the clouds what weather is coming in the next few hours.
