Main Page | See live article | Alphabetical index Humidity is the amount of moisture in the air. It can be expressed as absolute humidity, which is the mass of water in a specified volume or mass of air, or more commonly as relative humidity, which is the absolute humidity divided by that absolute humidity that would make dew form at the same temperature. See also: air conditioning, dew point, HVAC This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.