Humidity

Humidity generally describes the quantity of water vapour available in the air. Dry air has a very low quantity of water vapour while wet or humid air has high quantity of water vapour.

When human body sweats in a dry air, the sweat evaporates faster than when the air is damp and contain plenty of water vapour.  Humid air is a wet air while non humid air is a dry air.

Relative humidity.

Relative Humidity can be defined as the ratio of the mass of water vapour  present in a volume of air to the mass of water vapour required to saturate equal volume of the air at the same temperature.

 The degree of wetness   of air or humidity of the air describe the relative humidity of the air.

Relative humidity is used by Meteorologist to forecast weather.

Mathematically,

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