# How Much Does a Cloud Weigh?

Written by Nina Phillips
Published: November 11, 2023
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Clouds tend to look fluffy, like cotton candy. It’s easy enough to assume that clouds are also as light as cotton candy. However, if you somehow managed to weigh one, you’d find that’s not the case at all. Though you may expect the answer to “how much does a cloud weigh” to be fairly light, it’s much heavier than what you may expect.

Clouds are actually incredibly heavy. Though there is no way to know how much they weigh for certain, there are ways to get an estimate. Keep reading to find the answer to how much a cloud weighs.

## What Are Clouds?

Though clouds look light and fluffy, they are quite the opposite. Clouds are made up of water or ice crystals. As water evaporates from the surface of the earth, they go up in the air. Eventually, the vaporized water cools down and solidifies again. This is when it forms the clouds floating above you.

Though there is water vapor in the air, surrounding you all the time, it’s impossible to see with the naked eye. It has to be in high concentrations before it’s visible, which is why you can see clouds.

## The Average Weight of a Cloud

The average weight of a cloud is about one million pounds. This equals roughly the weight of 100 elephants. So every time you see a cloud floating above you, just remember that you have 100 elephants of cloud hovering above you.

Of course, this is just an estimation. Scientists calculate the weight of a cloud based on its density and size.

## Density Explained

In scientific terms, density is the mass of an object per unit of volume. In more simple terms, density is the relationship between how large and how much matter is in an object. Another easy definition is how tightly packed material is.

Think about a trash bag. When it fills to the top, there are plenty of spaces for air and small objects. This means the density is rather light. But, if you push the items in the trash can down, there’s a lot less open space between the trash.

Though the trash bag that’s overflowing with open spaces and the pushed-down trash weigh the same, they don’t have the same density. The one pushed down would be considered more dense.

In terms of clouds, this means that there’s a lot of open space between the water droplets, which makes it lighter than air. But, as more droplets enter the cloud, there’s less space between them, and the density increases. Eventually, it gets so heavy that it has no other option but to fall.

## Different Clouds Have Different Weights

The type of cloud also plays a role in their weight. Cirrus clouds are very light, for example. They usually have a lot less water in them per unit volume. Meanwhile, cumulonimbus clouds are much heavier.

## How Do Clouds Stay in the Air?

Even though clouds are heavy, they are actually lighter than the surrounding air. To be more accurate, they are heavier than the surrounding air but less dense.

### Density

Clouds, using cumulus clouds as the average, have a density of roughly half a gram per 35 cubic feet (or, half a gram per cubic meter). Meanwhile, the density of air is about 1,225 grams per 35 cubic feet.

As you can see, that means that clouds are far less dense than air. This is what allows clouds to float around in the air. Though clouds are made up of water, which is heavier than air, it’s dispersed enough to make the density less. The little water droplets in a cloud are about a millionth of the size of a raindrop.

As clouds go on, they collect more water and grow heavier. So what keeps clouds in the air as they get heavier? Nothing!

When clouds grow heavier than the air they are in, they start to fall. You might not realize it, as you’ve never seen a big cloud falling on your head, but clouds fall quite often.

Since clouds are just water, they fall by dropping excess water droplets. You may know this as rain. This is why the heavier clouds (cumulonimbus clouds) are the ones you see right before a storm.

Droplets in the air start to collect together and then fall to earth. They will continue to fall until the cloud is again a good weight and less weight than the surrounding air.

### Heat Convection

Heat convection also plays a large part in keeping clouds airborne. Warm air and water rise and move to the top of the cloud. Cold water sinks to the bottom of the cloud and provides a place for the warm water to sit.

Cold air, and water, is more dense than warm water and air. So the colder air sinks at the same time warm water is rising. This constant temperature change and floating allow the cloud to stay a bit lighter than it otherwise would and float more easily.

The cold water and the air at the bottom also give a solid foundation for warm air to push against. As warm air from the earth rises, it pushes against the cold bottom of the cloud, this gives the cloud a little lift and helps it stay in the air.

The photo featured at the top of this post is © AppalachianViews/iStock via Getty Images

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