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While all forms of precipitation start as snow high up in the clouds, there are four primary types that eventually reach the ground: snow, sleet, freezing rain and plain ol' rain.

Snow occurs when the atmosphere is "cold" all the way from the clouds to down here at the surface.

Sleet and freezing rain form because of a "warm-air sandwich" in the atmosphere above our heads. Precipitation starts as snow in the cold layer at the top, then melts to rain as it falls through the warm layer, then refreezes into sleet or freezing rain as it falls through the cold layer near the surface.

For sleet to occur, the warm air layer is rather thin. A thicker wedge of cold air beneath the warm air refreezes the partially melted snow into ice pellets.

For freezing rain to occur, the warm air layer is thicker. The snow melts into rain then refreezes just as it hits the cold ground.

Since the rain is not freezing until it reaches the surface, it still falls like regular rain and therefore looks and feels the same until it freezes on the ground.

Sleet is made up of ice pellets that bounce off objects. Even though this may sound more hazardous than freezing rain, that's not the case.

"Freezing rain is by far the most dangerous because it forms a solid sheet of ice, as opposed to sleet that just has small ice pellets that quickly bounce off of the surface," AccuWeather meteorologist Brett Anderson said. "Actually, sleet can even provide a little bit of traction for drivers, as opposed to the obvious dangers of a solid sheet of ice that forms from freezing rain."

Finally, when the air is warm enough all the way down to the surface, it's just plain rain that reaches down here.

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Ice pellets are a form of precipitation consisting of small, translucent balls of ice. Ice pellets are different from graupel ("soft hail") which is made of frosty white rime, and from a mixture of rain and snow which is a slushy liquid or semisolid. Ice pellets often bounce when they hit the ground or other solid objects, and make a higher-pitched "tap" when striking objects like jackets, windshields, and dried leaves, compared to the dull splat of liquid raindrops. Pellets generally do not freeze into a solid mass unless mixed with freezing rain.

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Hail is a form of solid precipitation.[1] It is distinct from ice pellets (American English "sleet"), though the two are often confused.[2] It consists of balls or irregular lumps of ice, each of which is called a hailstone. Ice pellets generally fall in cold weather, while hail growth is greatly inhibited during cold surface temperatures.[3]

Unlike other forms of water ice precipitation, such as graupel (which is made of rime ice), ice pellets (which are smaller and translucent), and snow (which consists of tiny, delicately-crystalline flakes or needles), hailstones usually measure between 5 mm (0.2 in) and 15 cm (6 in) in diameter.[1]

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Originally posted by wtg:
And you haven't lived until you've seen hoarfrost. It's the most beautiful thing in the world.

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Originally posted by RealPlayer:
I don’t think I’ve yet taken the opportunity to say welcome to the Midwest, Steve.