Where does rainwater come from?

Answer 1

The Sun's heat causes water to evaporate (dissolve) into the air (you can see this happen when your Mum hangs the washing out to dry). The wind then moves this 'wet' air up into the sky where it cools and the dissolved water comes out of the air (you can see this happen withe the steam that forms on the mirror when you take a bath or shower) - this forms the clouds you can see in the sky. When enough water comes together in the clouds, it gets too heavy to stay up and falls back to the ground as rain.

Answer 2

Rainwater comes from condensed water vapor in the atmosphere that forms clouds. When these clouds become saturated with water, the water droplets combine and become heavy enough to fall as precipitation, which can be in the form of rain, snow, sleet, or hail.