There are many forms of precipitation, some of which can easily be confused with others.

Whilst everyone knows the difference between rain and snow, some may not be familiar with the differences between these and other types of precipitation such as:

• drizzle
• sleet
• freezing rain
• snow grains
• snow pellets
• hail

Which of these we experience on the ground is determined by how raindrops and snowflakes are altered by atmospheric conditions as they fall.

Most people think of rain as any liquid drop falling from the sky, however, there is a distinct difference between rain and drizzle, and that is in their size. To be classed as rain, a drop must have a diameter of 0.5mm or greater, with anything under this considered drizzle.

The last of the purely liquid precipitation is freezing rain. If the cold layer under a cloud is too shallow for the droplet to completely freeze before it hits the ground, it instead hits the ground as a supercooled raindrop. When this drop hits a cold surface, it almost immediately freezes. For those wondering what it's called if the raindrop is smaller than 0.5mm - freezing drizzle. This leads us nicely into our frozen precipitation.

Snow is first up, and the one most people can readily identify. Snow is white or translucent ice crystals with complex hexagonal shapes, often joining together to form snowflakes.

Less obvious to identify are snow grains and snow pellets. Whilst these are both white or opaque, they differ in that they fall from different types of clouds and are different sizes. Snow grains are less than 1 mm in diameter whilst snow pellets are less than 5 mm in diameter.

Another form of precipitation that is more widely known is sleet (or ice pellets). Sleet forms when snowflakes, or frozen raindrops, partially melt as they fall, then refreeze before they hit the ground.

Rounding out the last of the list is the all too familiar hail. These ice particles come in various shapes from round to irregular lumps and can be transparent or opaque. Hail, unlike other types of precipitation, can vary in size significantly, from that of a pea up to baseball. Unlike previous types of precipitation, hail is almost always associated with a thunderstorm.