relative humidity
Americannoun
noun
-
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.
-
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:
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Big Sur’s micro-climate makes firefighting more complicated: The relative humidity drops at night, making fires grow rapidly.
From Los Angeles Times ● Aug. 28, 2026
The heat index is what the temperature feels like to the human body when relative humidity is combined with the air temperature.
From BBC ● Jul. 2, 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
“The temperature drops and the relative humidity goes up, the winds die down, flames drop to the ground and it starts creeping along,” Hanson said.
From Los Angeles Times ● Dec. 28, 2025
Fifty per cent relative humidity, therefore, signifies that only half the amount of vapor required to saturate the space at the given temperature is present.
From Seasoning of Wood by J. B. (Joseph Bernard) Wagner
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
