Relative Humidity
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Relative Humidity
(1) The amount of water vapor in the air compared to the amount of water vapor that the air can hold at a given temperature. For example, if the relative humidity is 50 percent, then the amount of water vapor in the air is half of what the air could actually hold at that temperature.
(2) The ratio of actual pressure of existing water vapor to the maximum possible (saturation) pressure of water vapor in the atmosphere at the same temperature, expressed as a percentage