What is "corn sweat" and how could it worsen the dangerous heat being felt across the Chicago area this week?
All of northern Illinois is under an excessive heat warning on Tuesday, but a phenomenon known as “corn sweat” will make the conditions even more challenging in areas away from the city of Chicago.
Here's what it is and how it could impact you:
What is corn sweat?
According to the Weather Channel, “corn sweat” refers to a process by which plants exhale water, the technical term for which is “evapotranspiration.”
Officials say that process peaks between mid-July and late-August, with each acre of corn potentially giving off up to 4,000 gallons of water per day.
What does it mean for Chicago-area weather?
Local
Heat indices could soar above 110 degrees and could even approach 115 degrees in some parts of the state on Tuesday, according to an excessive heat warning issued by the National Weather Service. Since heat indices are calculated using dew points and temperature, anything that adds extra moisture into the air can impact them.
And that’s where “corn sweat” comes in.
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The phenomenon adds extra moisture into the atmosphere, which can drive dew points up in areas where there is a lot of agricultural land.
In the Quad Cities, for example, the heat index reached nearly 110 degrees on Monday afternoon, with air temperatures in the low-90s and dew points reaching a steamy 80 degrees.
The entire state of Iowa was under an excessive heat warning on Monday and will see similar conditions on Tuesday as the high humidity couples with some of the hottest air temperatures of the season.
Iowa is ground-zero for “corn sweat” impacting conditions, but parts of Missouri, Minnesota, Wisconsin and Illinois can also be impacted.
What else to know about corn sweat
According to the National Weather Service's central Illinois office, mature Illinois corn crops "give off over 35 billion gallons of water daily into the atmosphere."
That's enough water to fill over 52,500 Olympic-sized swimming pools, the agency noted.
