Precipitation refers to any form of water, liquid or solid, that falls from the atmosphere to the Earth's surface. The main types include rain, snow, sleet, and hail. Rain is liquid water droplets that fall when clouds become heavy. Snow consists of ice crystals that form in cold temperatures and fall as flakes. Sleet occurs when raindrops freeze before reaching the ground, creating small ice pellets. Hail forms during thunderstorms when strong updrafts carry water droplets upward, where they freeze and accumulate layers of ice before falling. Each type of precipitation plays a crucial role in the Earth's water cycle.