In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravity.
Gravity, or gravitation, is a natural phenomenon by which all things with mass are brought toward one another, including planets, stars and galaxies.
Water is a transparent fluid which forms the world's streams, lakes, oceans and rain and is the major constituent of the fluids of organisms.
Condensation is the change of the physical state of matter from gas phase into liquid phase, and is the reverse of evaporation.
What is precipitation? by Met Office - Weather
The main forms of precipitation include drizzle, rain, sleet, snow, graupel and hail.
Snow pertains to frozen crystalline water throughout its life cycle, starting when it precipitates from clouds and accumulates on surfaces, then metamorphoses in place, and ultimately melts, slides or sublimates away.
Graupel, also called soft hail or snow pellets, is precipitation that forms when supercooled droplets of water are collected and freeze on falling snowflakes, forming 2–5 mm balls of rime.
Rain is liquid water in the form of droplets that have condensed from atmospheric water vapor and then precipitated—that is, become heavy enough to fall under gravity.
Precipitation Reactions: Crash Course Chemistry #9 by CrashCourse
Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and "precipitates".
Thus, fog and mist are not precipitation but suspensions, because the water vapor does not condense sufficiently to precipitate.
Fog consists of visible cloud water droplets or ice crystals suspended in the air at or near the Earth's surface.
Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air.
Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud.
In meteorology, a cloud is an aerosol comprising a visible mass of minute liquid droplets or frozen crystals, both of which are made of water or various chemicals.
Moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condensed into clouds and rain.
This process is typically active when freezing rain is occurring.
Freezing rain is the name given to rain that falls when surface temperatures are below freezing.
A stationary front is often present near the area of freezing rain and serves as the foci for forcing and rising air.
A stationary front is a pair of air masses, neither of which is strong enough to replace the other.
Provided necessary and sufficient atmospheric moisture content, the moisture within the rising air will condense into clouds, namely stratus and cumulonimbus.
Cumulonimbus, from the Latin cumulus and nimbus, is a dense towering vertical cloud associated with thunderstorms and atmospheric instability, forming from water vapor carried by powerful upward air currents.
Eventually, the cloud droplets will grow large enough to form raindrops and descend toward the Earth where they will freeze on contact with exposed objects.
Earth is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to harbor life.
Where relatively warm water bodies are present, for example due to water evaporation from lakes, lake-effect snowfall becomes a concern downwind of the warm lakes within the cold cyclonic flow around the backside of extratropical cyclones.
Lake-effect snow is produced during cooler atmospheric conditions when a cold air mass moves across long expanses of warmer lake water, warming the lower layer of air which picks up water vapor from the lake, rises up through the colder air above, freezes and is deposited on the leeward shores.
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain.
Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are low-pressure areas, which along with the anticyclones of high-pressure areas, drive the weather over much of the Earth.
Lake-effect snowfall can be locally heavy.
Thundersnow is possible within a cyclone's comma head and within lake effect precipitation bands.
Thundersnow, also known as a winter thunderstorm or a thundersnowstorm, is an unusual kind of thunderstorm with snow falling as the primary precipitation instead of rain.
In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation.
Windward is the direction upwind from the point of reference.
On the leeward side of mountains, desert climates can exist due to the dry air caused by compressional heating.
The Desert climate, also known as an arid climate, is a climate that does not meet the criteria to be classified as a polar climate, and in which precipitation is too low to sustain any vegetation at all, or at most a very scanty shrub.
A desert is a barren area of land where little precipitation occurs and consequently living conditions are hostile for plant and animal life.
Climate is the statistics of weather, usually over a 30-year interval.
The movement of the monsoon trough, or intertropical convergence zone, brings rainy seasons to savannah climes.
The monsoon trough is a portion of the Intertropical Convergence Zone as depicted by a line on a weather map showing the locations of minimum sea level pressure, and as such, is a convergence zone between the wind patterns of the southern and northern hemispheres.
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea.
The Intertropical Convergence Zone, known by sailors as the doldrums, is the area encircling the earth near the equator where the northeast and southeast trade winds come together.
Precipitation is a major component of the water cycle, and is responsible for depositing the fresh water on the planet.
Fresh water is naturally occurring water on Earth's surface in ice sheets, ice caps, glaciers, icebergs, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams.
The water cycle, also known as the hydrological cycle or the hydrologic cycle, describes the continuous movement of water on, above and below the surface of the Earth.
Approximately 505,000 cubic kilometres of water falls as precipitation each year; 398,000 cubic kilometres of it over the oceans and 107,000 cubic kilometres over land.
An ocean is a body of saline water that composes much of a planet's hydrosphere.