University of Illinois Extension

Relative Humidity

 Dew on grass

Dew on grass
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We describe how much water vapor is in the air by using the term relative humidity. Relative humidity tells us how much water vapor is in the air, compared to how much it could hold at that temperature. It is shown as a percent. For example, a relative humidity of 50 percent means the air is holding one half of the water vapor it can hold. Again, this is all dependent on the temperature.

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