Water evaporates from oceans, seas, rivers, etc., and rises up in the atmosphere. At the height of several thousand kilometres, these vapours condense to form clouds and eventually droplets. By this time, the droplet may have travelled many miles from its place of origin. Once the droplets reach a certain size, typically 6 mm in diameter, they begin to fall from a great height and would travel thousands of miles.
Evaporation to precipitation – Time taken by a droplet of water
