“How much does a cloud weigh?”
“Prepare to have your mind blown!”
Clouds are mostly made of water droplets that are so small you can’t see them individually. They are so small it would take about a billion of them to make one drop of rain.
Scientists have discovered that a typical fluffy white cloud contains about half-a-gram of water in each cubic metre. Let’s assume that a typical fluffy white cloud is a kilometre long, a kilometre high, and a kilometre deep (or 0.24 of a cubic mile). That adds up to approximately 500 tonnes of water.
The obvious question to ask is how does all of that water stay above the ground?
There are three main reasons. Firstly, the sun heats the ground during the day. This creates columns of rising air that keep the clouds aloft, as well as moving. Secondly, large volumes of moving air, such as a cold or warm front can push the clouds upwards. Finally, and importantly, the 500 tonnes of water is spread over a large area. The effect of gravity on each small water particle is next to nothing.
It rains when the droplets join together and get heavier than the forces that keep them aloft start to fail. This is a key part of the water cycle.
