Stop Making Fun Of Your Iowa Friends, Corn Sweat Is A Real Thing

I know it sounds crazy, but it's not weather science fiction. Corn sweat is actually a thing and we're feeling it right now.

Dew points and humidity levels are through the roof this week. An Excessive Heat Warning is in effect for a good portion of Iowa and Illinois. Heat index levels are expected to be between 110-115° as highs will be in the mid to low 90s. Yes, it's hot outside but what's making it worse is the corn sweat.

Technically, it's called evapotranspiration. NOAA defines evapotranspiration as the "Combination of evaporation from free water surfaces and transpiration of water from plant surfaces to the atmosphere." Simply put corn sweat. Sure, other crops like soybeans also do the same thing, we blame corn in Iowa and Illinois for one reason: there's a lot of it.

Why We Blame Corn For The Increased Humidity Level

Iowa farmers produced around 2.4 billion bushels of corn for grain. That comes from the 12.9 million harvest acres of corn according to the U.S. Department of Agricultural Statistics Service. Right behind Iowa is Illinois with the second most acres of corn. Illinois harvested 11 million acres of corn in 2023.

Yeah, that's a lot of corn.

No Way Corn Sweats That Much

Does corn really sweat that much? Meteorologist Kyle Kiel says, "According to the University of Illinois Extension of the College of Agricultural, Consumer, and Environmental Sciences, at its peak, corn can “sweat” or release up to four thousand gallons of water vapor, per acre, per day, into the atmosphere."

In Iowa alone, that's 51.6 billion gallons of water vapor released every day. Illinois corn crops sweat 44.2 billion gallons of water vapor. Combined that's 145,151.5 Olympic swimming pools of water vapor are released daily in Iowa and Illinois at peak corn maturity time.

More of a visual person? Same.

Here is a map of the U.S. and the dew points for today. As you can see, where the corn is and where the Great Lakes are, dew points are higher than the surrounding areas.

If you really want to see it in real time, check out this map here.