Rain is Liquid Water in the form of droplets that have condensed from Atmospheric Water Vapor and then become Heavy enough to Fall under gravity. Rain is a major component of the Water Cycle and is responsible for depositing most of the Fresh Water on the Earth. It provides suitable conditions for many types of ecosystems, as well as Water for hydroelectric power plants and crop irrigation.
The major cause of rain production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts.