The rainfall is given in 'mm', right - this means area has been controlled for? I.e. its the amount of rain, in milimeters, that would fall in a given area. Th

The rainfall is given in 'mm', right - this means area has been controlled for? I.e. its the amount of rain, in milimeters, that would fall in a given area. This is how rainfall is normally measured. Unless you are trying to say something more subtle, or making a joke?