Drowning in Corn Sweat
When I was a kid, we used to visit my father’s family in southern Illinois at least once a year—more often if there were funerals. They lived in the corn belt, on the rich black prairie, where the numbered county roads crossed at right angles, because there were no obstacles to go over or around. The farmhouses and barns were the only breaks in an unrelenting sea of corn, often taller than me.
We usually visited around Decoration Day—but a few times we were there in midsummer. Trust me, there is no place hotter in this world than southern Illinois in midsummer. You can talk about your Death Valleys and Phoenix, Arizonas, but that is, as they say, a dry heat. You may fry, but you won’t boil alive. And, unlike in Phoenix, nobody in southern Illinois had air conditioning back then.
I’m from Ohio, so I’m used to midwestern humidity—I’ve suffered a lifetime of bad hair days. But the humidity in southern Illinois is on a whole new level—like breathing through a warm wet washcloth. We’d sprawl in folding chairs in the shade in a relative’s back yard like cadavers washed up on a beach, unable to muster the energy to make another circuit of the potluck table.
The elders would be gathered indoors around a floor fan, telling stories I wasn’t supposed to hear. If I crept near enough to the fan to catch the breeze, it wasn’t much better—it was like being slapped in the face with a wet washcloth.
The only available refuge was our Pontiac station wagon, which was AIR CONDITIONED. But we weren’t allowed to sit in it with the AC running. So my brother and sister and I volunteered for every errand that involved getting into the car and driving somewhere—taking the long way. Need more soda? Whipping cream? Cigarettes? Beer? Your favorite pillow from Ohio?
And we would whine, “Why is it so HOT here?” This was long before people began fighting about global warming.
But now, mystery solved! More than half a century later, we have a possible explanation for the sauna-like heat in that part of the midwest: corn sweat, or evapotranspiration (ET.) It’s a real thing, and it’s getting a lot of press lately, from Minnesota to Peoria to Chicago, from the Washington Post to People Magazine.
Washington Post writer Ben Noll explains that corn exhales water vapor through its leaves, which increases humidity in agricultural areas. This process peaks during “tasseling” and “flowering.” (In all fairness, soybeans aren’t entirely innocent.)
Illinois grows about 12 million acres of corn, which could add up to 48 billion gallons of water daily – enough to fill 73,000 Olympic-size swimming pools, according to Taranis, a crop intelligence firm. No wonder we were drowning.
Corn has its defenders, though. The Ohio State University Extension climatologist Aaron B. Wilson says that it is very unlikely that “corn sweat” is contributing in any meaningful way to the recent stretch of muggy days. He’s blaming it on the Gulf of Mexico.
As far as I know, there is no consensus on whether corn sweats, perspires, or glows.
https://www.washingtonpost.com/weather/2025/07/21/corn-sweat-humidity-heat-wave-forecast/
https://extension.osu.edu/about/resources/corn-sweat-and-humidity-few-facts-explaine
I wish I could upload the Google maps photo that shows my tiny house in rural Ohio surrounded on every single side (for miles) by corn and soy fields. As I'm already dealing with menopause right now and hot flashes, the humidity is absolutely oppressive. I keep telling the neighbor kids to keep an eye on me when I'm out doing yard work - they may be the first ever to be eyewitnesses the phenomenon of spontaneous human combustion.
I used to stay with my grandmother in Flushing, Queens, during the summer. It was SO HOT in the city! Sidewalks, bus exhaust, her little fourth floor apartment. But I think you had it worse, Cinda.