Can ‘corn sweat’ worsen heat waves?

Yes.

Water evaporating off of corn, known as “corn sweat,” can exacerbate heat waves by adding moisture to the air. 

Known as “evapotranspiration,” the phenomenon occurs when water transfers from the corn’s surface or the soil to the atmosphere. This can result in higher dew points and humidity.

The crop can add as much as 4,000 gallons of water vapor to the air per acre each day. A study on a Midwestern heat wave in 2011 found moisture levels from crops rose by 40% over agricultural areas during daytime.

High dew points and humidity are common weather conditions each summer in Upper Midwest states, home to vast croplands. Minnesota is top five out of all states in corn and soybean production, giving it abundant sources of crop “sweat.” 

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Sources

• The Ohio State University Extension Corn Sweat and Humidity: A Few Facts Explained
• University of Illinois Extension How does corn affect Midwest weather?
• Journal of Geophysical Research: Atmospheres Quantifying the Impact of Excess Moisture From Transpiration From Crops
• Minnesota Department of Agriculture Minnesota Agricultural Profile

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