Sleet is frozen or partially frozen rain that falls as small ice pellets. When raindrops pass through a layer of freezing cold air near the ground, they turn into tiny balls of ice before hitting the earth. These pellets bounce off sidewalks, ping against windows, and make walking treacherous because they create a slippery coating on everything they touch.

Sleet falls during winter storms when the temperature hovers right around freezing. It's different from snow, which forms as delicate ice crystals high in the clouds, and different from freezing rain, which stays liquid until it hits the ground and then freezes into a slick glaze. Sleet arrives already frozen, making a distinctive tapping sound as it strikes surfaces.

A sleety day means miserable weather: not quite the beauty of a snowfall, but all the cold and slipperiness. Schools sometimes close during sleet storms because roads become dangerously icy. If you're outside when sleet starts falling, those little ice pellets can sting your face and make you want to run for cover.