Total precipitation
The total amount of precipitation in one year is 5,000 million million tonnes. Water changes from one form to another by evaporation, freezing, melting and condensation. It can be either water vapour gas, liquid water droplets or solid ice crystals.

  How much water vapour?
If all the water in the air fell at the same time it would cover the whole Earth with 25 mm (1 in) of rain.