The Difference Between Freezing Rain, Sleet, Snow, and Rain

From NWS Blacksburg VA

With just the upcoming threat of wintry weather, it's a good time to learn the difference between the common forms of precipitation we experience. 

• Rain:  When tiny droplets of frozen water collide and become too heavy to stay in the cloud, they fall to earth. The droplets will eventually move out of the freezing zone and into an area of warmer air. These droplets will turn to rain and if the warm air extends all the way to the surface, we will experience rain. 
• Freezing Rain: This process is almost the same as rain. The frozen droplets will also move out of the freezing zone and into an area of warmer air. When they get closer to the surface, they will enter an area of cold air and supercool. If the surface is frozen, freezing rain will form.
• Sleet: Sleet is similar to freezing rain. The droplets of frozen water fall out of the cloud and move through an area of warm air where they turn to rain droplets. The area of warm air is much smaller than it was in freezing rain. When the rain droplets move into an area of cold air, they have enough time to refreeze because the area of cold air is much larger than freezing rain. The pellets of ice will then hit the ground.
• Snow: Snow is the most simple one. When snow falls out of the cloud, it does not encounter an area of warm air. It will stay frozen all the way down and reach the ground as snow.

Source:  Earth Gauge