warm cloud

In meteorology, a warm cloud is a cloud composed entirely of liquid water droplets, even if the temperature is below freezing. The formation of precipitation in these clouds, known as warm-cloud processes, begins with condensation, where water vapor forms droplets. As these droplets grow, they can collide and merge with others, a process called collision-coalescence.1

When these droplets become large enough, they fall to the ground as rain. This type of precipitation is common in shallow cumulus clouds, particularly over tropical oceans where there's less competition for water vapor among condensation nuclei. Clouds, in general, form when moist air rises, expands, and cools to its dew point, causing water vapor to condense onto tiny particles called condensation nuclei.123