What layer of the atmosphere are clouds formed?

Clouds are primarily formed in the troposphere, which is the lowest layer of Earth's atmosphere, extending from the surface up to about 8 to 15 kilometers (5 to 9 miles) high. This layer contains most of the atmosphere's water vapor, and as warm air rises, it cools and condenses to form clouds. Various types of clouds can develop in this layer, depending on temperature, humidity, and atmospheric conditions.