Water from various sources such as lakes and oceans becomes water vapour because of the hot sun. The water vapour rises in the air because of evaporation and is retained in the same form but invisible until condensation occurs. Since the vapour cannot rise more than a certain height, it remains in the same height above sea level.

When the wind blows, whether it is warm or cold, it carries the droplets of water and raises it. In the open atmosphere in the sky, huge amount of water vapour formed by evaporation get together to form clouds. Since the air cannot hold these enormous tiny droplets of water, it transforms the droplets into foggy clouds! Clouds are nothing but the water droplets accumulated together. When this cloud touches the cold surface such as a mountain or the cold air itself when it rises up, condensation occurs. Therefore, the cloud becomes tiny water droplets and falls down. This tiny water droplets falling down from the sky is what we call rain.