Rain brings a multitude of benefits to the earth, including watering wild plants and crops, humidifying the air, creating streams and rivers, replenishing the water table and creating healthy negative ions. Perhaps the most important benefit of rain is its redistribution of fresh water in the water cycle.
Rain is formed when water that has evaporated from oceans, fresh water and land masses condenses in high, cool air, forming clouds. These clouds release rain, which rehydrates the land and air. Water is stored in the water table, the part of Earth's crust in which rocks and soil are constantly saturated with water. Water that cannot be stored in the water table becomes runoff, which feeds streams and rivers and ultimately the ocean. In short, rain delivers water in massive quantities to where it is needed to support life.
Plants draw the water they need to process sunlight into food from earth that has been saturated with rainwater, and animals survive on those hydrated plants as well as standing and running water delivered by rain. Rain cools air that has been overheated by sunlight, rehydrating dry leaves and grasses as well as feeding them. It supports freshwater fish and amphibians by keeping rivers, streams and swamps filled.
Humans have found other uses for rain. Running water fed in part by rainfall is used to create hydropower, and scientists are studying rainwater-produced natural lightning for ways its power can be harnessed and stored. Scientists are also looking at ways to produce rain by seeding clouds.