What does it mean if the relative humidity is 100%?

Relative humidity is a ratio of actual amount of water vapour (content) in the air compared to the maximum water vapour the air is able to hold (capacity) at that temperature. It is expressed as percentage. read more

Relative humidity does not tell how much water vapour is actually in the air. but, it tells how close the air is to being saturated. So, air is said to be saturated or full if relative humidity is 100%. read more

A relative humidty measurement of 100% does not necessarily mean that rain is falling. It just means that the air is holding as much moisture as it can at a given temperature, in the form of water vapor, which is an invisible gas. read more

The relative humidity (RH) is the ratio of the AH to the capacity 100. At 37 Celsius, the capacity is about 44 mg/L. If the AH is 22 mg/L, then the RH is 50%; (22/44) x 100. read more