Does It Snow on Other Planets?

At the top of mountains on the planet Venus, underneath a layer of thick clouds, is a layer of snow. But this is not the kind of snow that brings skiers to mountains on Earth. The atmosphere on Venus is so hot that water-based snow doesn’t exist. Instead, the "snow-capped" mountains on Venus glitter with two types of metal: galena (lead sulfide) and bismuthinite (bismuth sulfide).

Scientists say that this so-called snow is probably more similar to frost. On the lower Venusian plains, temperatures reach a searing 480°C (894°F) -- hot enough so that the reflective pyrite minerals on the planet’s surface are vaporized, entering the atmosphere as a kind of metallic mist, and condensing on mountaintops.

Are there snow days in space?

Maxwell Montes is the tallest peak on Venus, with an altitude of 11 kilometers (6.8 miles). That’s 3 kilometers (1.8 miles) higher than Mount Everest.

More than 96 percent of the Venusian atmosphere is carbon dioxide, and Earth’s sister planet has nearly 100 times as much atmospheric gas.

Snowflakes on Mars are smaller than their Earth counterparts -- roughly the size of a human red blood cell. They’re composed of carbon dioxide, not water.