Rain is a form of precipitation that occurs when atmospheric water vapor cools and condenses into liquid droplets that become heavy enough to fall from cloud systems. This process is integral to the global water cycle, beginning with evaporation from bodies of water and subsequent cooling to form clouds. Within the cloud, the droplets collide and aggregate, growing through a process known as coalescence. When the weight of these suspended liquid masses exceeds the air's resistance and updraft forces, the precipitation falls to the surface. The resulting water profoundly impacts terrestrial environments by replenishing freshwater sources, driving biochemical processes, and influencing global climate patterns.