How Much Does a Cloud Weigh?

©. Peangdao

The answer may surprise you.

I have spent a lot of time looking at clouds. Yet in all of my pondering, somehow I never questioned how much one might weigh. They seem virtually weightless; how else would they crawl so effortlessly across the sky? Of course if we take a moment to think about it, clouds are made of water and water is heavy. But their floaty nature defies the obvious; in the way our brain understands the world, the logic of something heavy floating high above just doesn't compute at first.

If they are heavy like water, what are they doing up there?

As it turns out, our cloud friends are super heavy. How much so? A big, fluffy cumulus cloud weighs as much 300 midsize cars.

As explained in the American Chemical Society/PBS video below, a cumulus cloud has a density of 0.05 grams to 1,000 liters. The average cumulus cloud is around 1.24 miles (2 kilometers) wide, 1.55 miles (2.5 kilometers deep), and 219 yards (200 meters) tall. That equates to a volume of about one trillion liters, which ends up holding around 500 million grams of water; or around 1.1 million pounds.

How these hulking collections of water stay in the sky is nothing short of magic ... or, well, science. We can thank the ideal gas law, and a constant cycle of updraft and condensation / downdraft and evaporation; which is nicely illustrated in the video.

I'm not sure I will ever look at clouds in the same way again. Fluffy little lightweights? No way, these things are big beautiful beasts! #respect