relative humidity

American  

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 British  

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 Scientific  

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

---

Etymology

Origin of relative humidity

First recorded in 1810–20

---

Compare meaning

How does relative-humidity compare to similar and commonly confused words? Explore the most common comparisons:

• relative humidity vs. absolute humidity
• specific humidity vs. relative humidity

---

Example Sentences

See Examples For:

relative humidity

The fabric did not reduce light availability or negatively affect relative humidity.

From Science Daily ● Oct. 1, 2026

Big Sur’s micro-climate makes firefighting complicated: The relative humidity drops at night, making fires grow rapidly, Silveira has said.

From Los Angeles Times ● Aug. 29, 2026

Tropical Storm Elida has been a factor in the rise in relative humidity in the Los Angeles and the San Francisco Bay areas, weather service meteorologists said.

From Los Angeles Times ● Jul. 20, 2026

These included educational attainment, median household income, racial composition, average temperature and relative humidity, smoking prevalence, BMI, and distance to the nearest hospital.

From Science Daily ● Feb. 24, 2026

It may be carried further, however, by heating in partially humidified air, proportioning the relative humidity each time it is heated to the degree of moisture present in the wood.

From Seasoning of Wood by J. B. (Joseph Bernard) Wagner

Random Word

Spin the wheel and learn a new word!

---