Researchers from Iowa State and the University of Iowa say there's actual science behind that age-old midwest weather axiom that "it's not just the heat, it's the humidity." ISU Agronomy professor and Climate Science Program director Gene Takle says their studies show that climate change is making that humidity worse in all seasons of the year, most noticeably in spring and summer. He says rising humidity has all sorts of negative effects from more allergens in the air to an increase in black mold in homes. Takle says there's also some irony in the fact that increasing humidity causes heavier and more severe rain events, which causes more humidity.