relative humidity


Definition of relative humidity

: 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 Most of the fire activity is being driven by the record low moisture content of the vegetation in the area combined with high temperatures and low relative humidity. Eric Todisco,, "Thousands Told to Evacuate as Apple Wildfire Rages in SoCal with Over 25,000 Acres Burned," 3 Aug. 2020 According to studies from the National Institutes of Health, mosquitoes survive best at temperatures between 50-95°F and a relative humidity of 42% or more. Paul Douglas, Star Tribune, "Saturday Thunder Potential - "Isaias" Threatens Florida and Carolinas," 30 July 2020 The relative humidity, a measure of how moist the air is, shows average August humidity in Phoenix is 36 percent of capacity. Ronald J. Hansen, azcentral, "Republican National Convention coming to Phoenix? Here's what we know," 4 June 2020 Strong winds, up to 30 mph, and relative humidity in the 10% to 15% range are among factors driving the warning. Kieran Nicholson, The Denver Post, "Weather: Fire warning posted for southwest Colorado, Denver high temps in 80s by Thursday," 28 Apr. 2020 The National Weather Service said the combination of high temperatures and high relative humidity will lead to the heat index rising to between 95 and 100 Friday. Sarah Brookbank, The Enquirer, "Cincinnati weather: Another hot and humid weekend ahead," 11 July 2020 The difference comes when relative humidity is factored in, which will be a seasonal 60 percent by 2 p.m. Jay R. Jordan, Houston Chronicle, "Triple-digit ‘feels like’ temps in Houston on Tuesday," 30 June 2020 However, fire officials did express concerns about conditions that could make suppression efforts more difficult, specifically the low relative humidity and high winds forecasted for Monday morning. Alana Minkler, azcentral, "Bighorn Fire swells to 17,000 acres with 0% containment," 7 June 2020 Criteria for a Red Flag Warning include a relative humidity less than 15%, warm temperatures and high winds for several hours, combined with dry vegetation in the area. Audrey Jensen, azcentral, "Red Flag Warning issued for northern Arizona Friday and Saturday," 12 June 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'relative humidity.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of relative humidity

1819, in the meaning defined above

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Time Traveler for relative humidity

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The first known use of relative humidity was in 1819

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Statistics for relative humidity

Last Updated

12 Aug 2020

Cite this Entry

“Relative humidity.” Dictionary, Merriam-Webster, Accessed 12 Aug. 2020.

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More Definitions for relative humidity

relative humidity


Medical Definition of relative humidity

: 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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