Clouds are classified into different types based on their appearance and altitude. The main types include cumulus, stratus, and cirrus. Cumulus clouds are fluffy and white, often resembling cotton balls, and usually indicate fair weather. Stratus clouds are flat and gray, covering the sky like a blanket, often bringing light rain. Cirrus clouds are thin and wispy, found high in the atmosphere, and can signal a change in weather. Each cloud type plays a role in the Earth's weather system, helping meteorologists predict conditions and understand climate patterns.