What Are Cirrus Clouds Made Of

Cirrus clouds are the thin, wispy clouds you often see high up in the sky. They look like feathers or delicate brushstrokes stretched across the blue sky. But what are these clouds made of?

Unlike low clouds that are made mostly of water droplets, cirrus clouds are made of ice crystals. That’s because they form very high in the atmosphere, usually above 20,000 feet (6,000 meters), where the air is extremely cold. At these high altitudes, water vapor freezes into tiny ice crystals instead of turning into liquid droplets.

Cirrus clouds form when moist air rises very high into the sky and cools down. As it cools, the water vapor changes into ice crystals, which spread out into thin layers or streaks. Wind at those heights often stretches the clouds into their familiar wispy shapes.

Even though cirrus clouds don’t produce rain or snow at ground level, they can be a sign that a change in the weather is coming. For example, cirrus clouds sometimes appear before a warm front or a storm system, giving people a clue that rain might be on the way in the next day or two.

Because they are so high, cirrus clouds often catch sunlight in special ways—sometimes glowing pink, orange, or gold during sunrise or sunset.

Fun Fact: The name “cirrus” comes from Latin and means “curl of hair,” which describes their thin, curly appearance!