The millions of acres of corn grown in states like Ohio, Illinois and Iowa perspire just like any other plant. A single acre sweats 3,000 to 4,000 gallons of water every day.

A heat dome — plus the "corn sweat" phenomenon — is bringing dangerous levels of heat and humidity to Indiana on Thursday.

Sometimes humidity from corn can lead the temperature to be one to two degrees cooler, Izzi said, but added humidity likely results in a higher heat index.