How Much Do Clouds Weigh? It Depends On The Type

From cirrus wisps to stratus blankets to cumulus puffs, clouds generally look lighter than air, unless there's a dark nimbus cloud dumping rain on you. With an understanding of how clouds are made, we know that they consist of a large amount of small water droplets, tiny ice crystals, or both. These components have mass, so it only makes sense that clouds weigh something, too.

There are two parts to determining how much clouds weigh: cloud dimensions and water content. You can find the length, width, and height of a cloud based on its shadow on the ground, with a 1-kilometer shadow equaling 1,000 meters. The water content is harder to figure out because it varies according to the densities of the different types of clouds. On top of that, the temperature can change the mass of water. While it can vary, scientists follow a general consensus of water content per cubic meter for each cloud type: cirrus have 0.03 grams, stratus contain 0.2 grams, and cumulus contain 0.5 grams.

With these measurements, it's possible to determine the weight of a cloud. For instance, let's say that each dimension for a cloud is 1,000 meters. You can multiply each dimension together (1,000 x 1,000 x 1,000) to determine the volume or density, which is 1 billion cubic meters in this case. Then, you multiply that volume by the water content of the cloud based on its type, which turns out to be about 22 tons for cirrus clouds, 330 tons for stratus clouds, and 550 tons for cumulus clouds.

It's impressive that cirrus clouds can weigh about as much as a commercial jet or large trash truck, never mind that fair-weather cumulus clouds weigh the equivalent of two average train engines or two Statues of Liberty. With that knowledge, you might feel brazen staring up at them, but there are a few reasons why clouds don't fall on you.

For starters, that heavy mass is spread across a very large area, so the specific weight for any amount of volume is rather small. You wouldn't want to be standing underneath it, though, if it was compressed, at which point it would fall. Second of all, the tiny water droplets and ice crystals are so small, measuring about 1 million times smaller than a drop of rain, that gravity doesn't exert enough force to cause them to fall. It's like dust floating in sunlight or a feather falling slower than a pebble: Objects fall at a speed relative to their surface area and mass.

Third of all, clouds are less dense than the dry air below them. It works the same way as warm air rising and cold air sinking. Warm air and water droplets aren't as dense as cold air and water droplets, so they hover like bubbles in a bath. Over time, though, the water content of clouds increases, making the droplets heavier and bigger, which is when we get rain.