Rain
Rain is precipitation of liquid from the atmosphere which falls to the ground. It is caused by condensation of the liquid when the humidity passes the saturation point of the air it is in.

On most class M planets, rain is in the form of liquid water. On class M planets nucleogenic particles are necessary to produce rain; without them a planet would be incapable of producing any rain at all. Some forms of technology are capable of destroying nucleogenic particles. The Caretaker's race caused this damage to the Ocampan atmosphere, and as such it had no rain. ()

Ferenginar was well known for its near-constant rain. Because of the extremely rainy climate of their homeworld, the Ferengi had 178 different words for rain in all its various forms, including "glebbening". They also had no word for "crisp," as all food on Ferenginar became soggy very quickly. () In 2375, an accident at a power plant there produced toxic rain. ()

On , in the Delta Quadrant, rain storms were called "cloudbursts." ()

Many planets, such as Caldos and Risa, had weather control systems which, among other things, controlled rainfall. (; )

In 2373, Michael Eddington lamented the lack of rain and too much of it on a planet in the Demilitarized Zone. ()

In an alternate timeline in which Benjamin Sisko suffered temporal displacement, Melanie visited Jake Sisko on a particularly rainy night in 25th century New Orleans. ()

See also 
 Acid rain
 Rainforest

External link 
 

de:Regen
Meteorology