Units for humidity

Answer 1

Different types of humidity (specific, relative, and vapor pressure) are all measured with different units, although weathermen usually express the relative, which is measured as a percentage.

For further help, I've attached a link in the related links below.

Answer 2

Humidity can be defined in different ways, but humidity simply means the amount of water vapor present in the air:


Absolute humidity is the mass of water vapor in the unit volume of air. Its SI units are g/m3, but any mass per volume unit could be used.


Relative humidity is the ratio of the absolute humidity to the maximum absolute humidity for that temperature and pressure. It is expressed as a percentage. It is of limited utility in weather reporting, despite its unfortunate ubiquity, because it depends on both air temperature and vapor content and therefore changes when either or both of these terms change.

Dew point temperature is the temperature at which water vapor would condense if the air were cooled to it. Being a temperature, it is expressed as F, C, or K.


Specific humidity is similar to absolute humidity, though you rarely see this in everyday life. It is the ratio of water vapor to dry air, both in terms of mass (whereas absolute humidity is mass/volume). It is usually expressed as kg/kg, which is the SI unit.


Mixing ratio is similar to specific humidity and can be approximated by this term. It is a dimensionless ratio of water vapor to dry air and is often used in operational meteorology to diagnose certain meteorological quantities throughout the atmospheric column relative to the vapor pressure and saturation vapor pressure of the air.




-----
The lowest measured relative humidity in Phoenix, AZ, USA, is 2%--pretty dry. Sometimes the dew point is below 0 degrees, also pretty dry. (Celsius or Fahrenheit? Both!)

Answer 3

There are several ways of measuring humidity:

Absolute humidity is measured in [ML-3] usually grams per cubic metre.

Relative humidity and specific humidity are both pure ratios and so have no units.

Answer 4

There are three types of humidity measurement depending on the purpose and the circumstances:

• Absolute humidity is expressed in terms of grains per pound of air, ppm, or vapour pressure.
• Relative humidity is expressed as a percentage from 0% to 100%. It is the amount of moisture in air divided by the total possible amount of moisture in air.
• Dew point is a centigrade or fahrenheit temperature at which water condenses from the air.

Answer 5

Usually "percent" which is the percentage of water in the air which can be retained in the air without it condensing (to a fog). Otherwise, grams/litre.