Relative Humidity

 

What does relative humidity mean?

The relative humidity indicates the amount of water vapour in the air at any given moment as a percentage of the maximum amount it can contain.

The amount of water vapour which the air can contain depends very much on the temperature and the air pressure. That is why it is referred to as relative air humidity, which describes the amount of water vapour currently in the air in terms of a percentage of the maximum possible amount the air can contain under the current circumstances.

Relative air humidity therefore does not represent an absolute humidity level. 100% relative air humidity would mean that the air cannot hold any more water vapou at the moment, and that it is therefore saturated.