What are clouds made of?

Clouds are formed from billions of minute water droplets and tiny ice crystals that float together in the air. Each of the droplets in a cloud is about 100 times smaller than a raindrop. In general, low-level clouds, or those that are lower than 6,000 feet (1,828 meters) above the ground, are mostly made of water droplets. However in cold weather, they can also contain small snow and ice crystals. Mid-level clouds, or those between 6,000 and 20,000 feet (1,828 and 6,096 meters), are composed of water droplets during the summer months but have a high concentration of ice crystals during winter. High-level clouds above 20,000 feet are largely made of ice crystals. In addition to carrying water and ice crystals, many clouds contain small quantities of solid particles such as smoke and dust.