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
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
Temperatures dipped and relative humidity climbed, offering the possibility of a tamer fire to battle.
From Los Angeles Times ● Sep. 8, 2025
Those conditions will be particularly challenging when combined with low relative humidity, little cooling at night and a dry landscape.
From Los Angeles Times ● Aug. 19, 2025
Thus, the rainforests of the isthmus are characterized by a much higher relative humidity than are the savannas or semi-arid scrub forests.
From A Distributional Study of the Amphibians of the Isthmus of Tehuantepec, Mexico by Duellman, William E.
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.
