When I lived in Wisconsin and the summer weather turned exceptionally hot and humid, we always blamed the cornfields in Iowa for the high humidity. In fact, we were right! The Corn Belt puts a lot of water into the air as all those corn plants transpire water into the atmosphere. In fact, if you look at the Corn Belt as a whole, you will see that even though humidity is high, the temperatures are actually somewhat cooler than surrounding areas due to the effect of all that moisture in the air. You can read more from Barb Mayes Boustead in the Washington Post at What is corn sweat and why it’s making the Midwest so humid – The Washington Post
