relative humidity

noun

1. the amount of water vapor in the air, expressed as a percentage of the maximum amount that the air could hold at the given temperature; the ratio of the actual water vapor pressure to the saturation vapor pressure. : RH, rh

relative humidity

noun

1. the mass of water vapour present in the air expressed as a percentage of the mass that would be present in an equal volume of saturated air at the same temperature Compare absolute humidity

relative humidity

1. The ratio of the actual amount of water vapor present in a volume of air at a given temperature to the maximum amount that the air could hold at that temperature, expressed as a percentage. Warm air can hold more water vapor than cool air, so a particular amount of water vapor will yield a lower relative humidity in warm air than it does in cool air.
2. Compare absolute humidity

Word History and Origins

Origin of relative humidity¹

First recorded in 1810–20

Example Sentences

These conditions may be a high wind, low relative humidity, high temperatures, or a combination of the three.

From Project Gutenberg

They were the entranced William and Miss Pratt; and their appearance offered a suggestive contrast in relative humidity.

From Project Gutenberg

This cellar should have a temperature of 58° to 64° F. and a relative humidity of 95 per cent of saturation.

From Project Gutenberg

Further draining is best accomplished in a room at about 64° F. with a relative humidity of 85 to 90 per cent.

From Project Gutenberg

The cellars are wet, since they reach 90 to 95 per cent relative humidity at a temperature of about 55° F.

From Project Gutenberg