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. (VOY: "Caretaker")
Ferenginar is well known for its near-constant rain. Because of the extremely rainy climate of their homeworld the Ferengi have 178 different words for rain in all its various forms. They also have no word for "crisp," as all food on Ferenginar becomes soggy very quickly. (DS9: "Let He Who Is Without Sin...", "Family Business", "The Magnificent Ferengi", "Valiant") In 2375, an accident at a power plant there produced toxic rain. (DS9: "The Dogs of War")
On Banea, in the Delta Quadrant, rain storms are called "cloud bursts." (VOY: "Ex Post Facto") The term "cloud burst" is used on Earth to describe sudden, extreme, and often short lived rainfall as well.