human
Can you tell me about the different types of clouds?
assistant
Clouds are formed when tiny water droplets or ice crystals in the atmosphere grow large enough to become visible. There are several main categories of clouds, including cirrus, cumulus, stratus, and nimbostratus. Cirrus clouds are high-altitude wispy clouds that appear as thin, delicate strands. Cumulus clouds form when warm air rises into cooler air and condenses around small particles such as dust and water vapor. Stratus clouds are low-level clouds that can be seen from below, often appearing as a gray or even white layer. Nimbostratus clouds are thick, dark clouds that usually cover the sky at night and sometimes during the day.