Water that falls from a cloud is called "precipitation" and may take the form of rain, drizzle, hail, sleet or snow. Whether it falls as one or the other, depends on conditions inside the cloud and the temperature of the air outside it. The height at which water freezes as it condenses out of a cloud is called the "freezing level." The ice crystals grow rapidly into snowflakes as water droplets freeze onto them. If the freezing level is below 1,000 ft., the ice crystals will not have time to melt before reaching the ground and will fall as snow.

If the base of a stratus cloud is low enough, small droplets of rain may fall as a fine drizzle. Dry snow may fall as a afine drizzle. Dry snow falls when the ground temperature is cold, but if snow falls from a cloud into air that is just above freezing, some of it will melt. The resulting mixture of snow and rain is called "sleet."