Every summer, just as the Midwest becomes a sticky cauldron of heat, corn fields across Iowa and Illinois make things worse by unleashing a deluge of invisible moisture into the air. This phenomenon is affectionately, a bit misleadingly, and definitely disconcertingly dubbed “corn sweat.”
If you’re picturing ears of corn covered in perspiration while wearing sweat bands and gym shorts, you are extremely far off from what corn sweat actually is. To be fair to you, the name does not do a great job of describing the phenomenon.
The scientific name for this sticky mess is “evapotranspiration,” and it happens when plants like corn and soybeans release water vapor through their leaves. When you’re growing millions of acres of corn, that’s a lot of vapor. In Iowa alone, those corn stalks can pump out an absurd 49 to 56 billion gallons of water into the atmosphere every single day during peak season. That’s enough to fill 73,000 Olympic swimming pools in Illinois.
Of course, the corn doesn’t sweat, dripping with perspiration, the way we do after walking out in the hot summer sun. It’s invisible water vapor that wafts into the air, without leaving a physical trace other than a noticeable upward shift on a thermostat.
All that moisture mixes with the air, hikes up the dew point, and makes already hot days feel like you’re living inside a sauna that’s been cranked to the max. This can push the heat index up to 115°F, like it did across Illinois this month. The sun does its part, making things hot as hell, but then the cornfields quietly, innocently, crank the humidity up beyond all reason.
Corn sweat isn’t solely to blame for this. In an email exchange with USA Today, Iowa State climatologist Justin Glisan said that regional weather patterns, like moist air drifting in from the Gulf of Mexico, are still mostly responsible for skyrocketing summertime humidity levels. Corn sweat is mostly just a localized annoyance.
Where there is corn and excessive summertime heat, there is excessive summertime corn-based water vapor making matters worse.
Strangely enough, for as bad as the temperature and humidity can get in corny portions of the Midwest, the presence of evapotranspiration is actually a good thing. It means the crops are healthy and growing strong. The trade-off for being able to eat all that delicious corn is that the area around cornfields becomes a little more miserable to exist in for a few months.
The post Corn Sweat Is Making Midwest Heat Waves a Lot Hotter appeared first on VICE.
