The heat wave baking the central United States this week may feel worse than those earlier in the summer, and corn is partly to blame, forecasters say.

July has already been more humid than average, and now another, less obvious factor will enhance humidity this week: corn sweat. Like a person breathing, corn exhales water vapor through its leaves — a process called evapotranspiration — which exacerbates humidity in agricultural regions during the summer.

The heat will be most severe along and southeast of the I-99/US-220 corridor, where heat index values are likely to exceed 100 degrees. Residents are advised to take precautions such as staying hydrated, avoiding prolonged outdoor exposure, and checking on vulnerable populations like elderly neighbors and those without air conditioning.