relative humidity

noun

: the ratio of the amount of water vapor actually present in the air to the greatest amount possible at the same temperature

Examples of relative humidity in a Sentence

Recent Examples on the Web
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Dry conditions also persist, with relative humidity between 9% and 15%. Darrell Smith, Sacbee.com, 11 June 2026 In summer, a basement's relative humidity should be kept below 60 percent to prevent the growth of mold. Brandee Gruener, Southern Living, 10 June 2026 The National Weather Service issued a red-flag warning Tuesday for the East Bay hills and the interior mountains of the North Bay, citing high winds and low relative humidity that could quickly exacerbate any small fire started. Rick Hurd, Mercury News, 9 June 2026 After hikers discovered the mummy in 1991 along the Austrian-Italian border, the remains were stored at the South Tyrol Museum of Archaeology in Bolzano, where it was frozen at about 21 degrees Fahrenheit (minus 6 degrees Celsius) with 99% relative humidity. Mindy Weisberger, CNN Money, 8 June 2026 See All Example Sentences for relative humidity

Word History

First Known Use

1819, in the meaning defined above

Time Traveler
The first known use of relative humidity was in 1819

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Cite this Entry

“Relative humidity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/relative%20humidity. Accessed 16 Jun. 2026.

Kids Definition

relative humidity

noun
: the amount of water vapor actually present in the air compared to the greatest amount possible at the same temperature

Medical Definition

relative humidity

noun
: the ratio of the amount of water vapor actually present in the air to the greatest amount possible at the same temperature compare absolute humidity

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