Precipitation is any form of moisture which falls to the earth. This includes rain, snow, hail and sleet.
Precipitation occurs when water vapour cools. When the air reaches saturation point (also known as condensation point and dew point) the water vapour condenses and forms tiny droplets of water. These tiny droplets of water from clouds.
Complex forces cause the water droplets to fall as rainfall.
All rain is the same. It happens as the result of warm, moist air being cooled, leading to condensation and in turn rain. The following examples show three different ways air is cooled causing rainfall.