Sleet
Sleet, frozen or partly frozen rain. Sleet occurs in cold weather when raindrops freeze as they fall through cold air. The ice pellets that form are generally 15 inch (5 mm) or less in diameter. Sleet differs from freezing rain, which occurs when raindrops freeze upon landing on a cold surface. It also differs from hail, which consists of small lumps of ice that form during thunderstorms in warm weather.