How does rain form? The water cycle

Rain begins in the sea, lakes and rivers. The Sun warms the water, and some of it turns into an invisible gas called water vapour. This is evaporation.

The warm vapour rises high into the sky, where the air is cold. There, it cools and turns back into tiny droplets of water. Millions of these droplets together make a cloud. This is condensation.

Inside the cloud, droplets bump into each other and join. When they grow too heavy to float, they fall as rain. This is precipitation.

The rain flows back into rivers and the sea, and the cycle starts again. Kerala’s monsoon is this cycle on a giant scale: winds from the Arabian Sea carry huge amounts of vapour over the land, and the Western Ghats push the air up, cool it, and squeeze out the rain.