An acre of corn can release 3,000 to 4,000 gallons of water into the atmosphere a day, increasing humidity levels.

The process -- known by the scientific term "evapotranspiration" -- is the natural process by which plants move water from the roots of the plant to the surface, according to Ohio State University. The water then evaporates into the atmosphere, making the local region feel more humid.

Corn sweat, a Midwestern phenomenon, could increase humidity levels in already-sweltering states—from Ohio to Illinois—through Thursday.