There is actually a very fine line when it comes to what type(s) of precipitation you will experience depending on the temperature of the atmosphere above you. In this web article, we will be discussing how precipitation changes from one type to another for the following four: rain, freezing rain, sleet, and snow.
Before we dive into each type of precipitation, it’s good to have a general understanding of the atmosphere. Now, this isn’t for the entire atmosphere, just the section where weather occurs, which happens to be the troposphere. The troposphere is the section that starts at the surface of the earth and reaches up to 4-12 miles high. Within that space, there is a difference in temperature from the top to the bottom. How the temperature varies within that space is how we receive different precipitation types.
Rain: The closer you are to the top of a cloud, and even the top of the troposphere the colder the air will be. This doesn’t mean every raindrop is actually melted snow at all though. In simple terms, regular rain is evaporated water, condensed in a cloud. When the droplets get too heavy they fall, thus we get rain. This also means that as the raindrop falls, the air it falls through is above a freezing temperature and stays liquid. Fun fact: raindrops are shaped like pancakes/hamburgers.
Freezing Rain: This is a very dangerous type of precipitation. In this case, there is a section of warm air, just like with normal rain, but there is also a section of below-freezing air right at the surface. This means the raindrop will freeze upon the impact of whatever it lands on, like roads, creating dangerous driving conditions. Freezing rain tends to cover everything in a layer of ice, which thickness depends on how much precipitation there is.
Sleet: Sleet is very similar to freezing rain but has one key difference, the section of below-freezing air is larger. With this larger section, the droplets have more time to refreeze after they have melted, after passing through the warm section of air. The now frozen droplets have turned into ice pellets of a sort, not the flurries you think of when snow occurs. This precipitation type is also extremely dangerous for roads and other forms of travel.
Snow: Finally we get to snow, which is almost exactly like rain, just opposite. Instead of a section of warm air, the entire atmosphere from cloud to the ground is below freezing. This allows the already frozen droplets to collide and collect with other frozen droplets which then get heavy and fall out of the cloud. Thus, producing the flurries and snowflakes we have all come to understand as snow.