Most clouds stay in the troposphere, the 10-mile (16-kilometer) layer of the atmosphere nearest Earth.
Clouds are classified by height as well as shape. Cumulus clouds of fair weather, congested cumulus, and the lower parts of a cumulonimbus cloud will all form below about 6,500 feet (1,981 meters), along with stratus, stratonimbus, and stratocumulus.
The family of mid-height clouds include altocumulus (high cumulus), altostratus (high stratus), and the midsection of cumulonimbus. The middle section extends up to 23,000 feet (7,010 meters) above Earth’s surface.
High clouds, above 23,000 feet (7,010 meters), are cirrus, cirrocumulus, cirrostratus, and the top of cumulonimbus. Yes, the cumulonimbus can reach through all three layers of the troposphere.
They can actually poke their way into the stratosphere, growing as tall as 65,000 feet (19,812 meters).