On planet earth, water from the rivers, seas, and oceans is always evaporating. As these water droplets evaporate, they rise in the atmosphere towards the sky. Normally, our atmosphere also contains lots of tiny particles, some of which are able to attract water droplets and attach to them. Over time, these clusters of droplets become large, forming clouds that we see in the sky. Eventually, the clouds acquire too much water, and some process happens that makes the clouds lose their water in the form of rain. If the temperature outside is very cold, this rain freezes instantly and becomes snow. This is how rain and snow is made.