relative humidity
Americannoun
noun
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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.
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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.
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
“Today we’re experiencing lower winds and higher relative humidity, so we’re seeing reduced fire behavior,” said Dowd.
From Los Angeles Times ● May 22, 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
Meteorologists in the US and elsewhere have expressed concerns over "reduced number of weather balloons" that observe wind, relative humidity and pressure above the ground.
From BBC ● Jul. 6, 2025
The main things influencing evaporation are, first, the quantity of heat supplied and, second, the relative humidity of the immediately surrounding space.
From Seasoning of Wood by Wagner, J. B. (Joseph Bernard)
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.
