Precipitation is any form of liquid or frozen water that forms in the atmosphere and falls back to the Earths surface due to gravitational pull. The main forms of precipitation include:

• Rain: Rain is liquid water droplets that fall when temperatures in the air and at the surface are above freezing (32°F, 0°C) . It can start as water droplets or ice crystals in a cloud but always falls as liquid water.

• Snow: Snow is frozen water that falls when temperatures in the air and at the surface are below freezing (32°F, 0°C) . Snowflakes form when water vapor in the air freezes into ice crystals, which then grow into snowflakes as they fall through the atmosphere.

• Sleet: Sleet is icy precipitation that forms when a thin layer of warmer air comes between layers of cold air. A top layer of below-freezing air creates ice crystals that melt as they fall through a thin layer of above-freezing air. If theres enough room between the warmer air and the ground, the water droplets re-freeze in a bottom layer of below-freezing air and fall as sleet.

• Hail: Hail is frozen precipitation that forms in thunderstorms when strong updrafts carry raindrops high into the atmosphere, where they freeze into ice. The ice falls back down to the ground, but if it gets caught in another updraft, it can be carried back up and grow larger as more water freezes onto it. This process can repeat several times, creating hailstones of different sizes.

• Drizzle: Drizzle is light rain that falls in very small droplets.

• Graupel: Graupel, also known as soft hail or snow pellets, is precipitation that forms when supercooled water droplets freeze onto falling snowflakes, creating small, round pellets of ice.

Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, reaching 100% relative humidity, so that the water condenses and "precipitates" or falls. Precipitation is a major component of the water cycle and is responsible for depositing most of the fresh water on the planet.