This week’s dangerously hot conditions may be even hotter in communities with corn fields.
MISSOURI, USA — Extreme heat warnings and heat advisories loom over the entire state of Missouri. Corn field communities will be hotter than everyone else.
Dangerously hot conditions, with heat index values up to 110 degrees, are expected in numerous counties on the eastern half of Missouri, according to the 5 On Your Side Weather Impact Team. The warning runs through 7 p.m. on Thursday, although it could be extended as the heat is expected to stay throughout the weekend.
Rural communities with corn fields may experience even hotter conditions thanks to a phenomenon called “corn sweat.”
Corn plants need one-and-one-quarter inches of rainfall in July and August to maintain rapid growth and produce the best possible yields, according to the University of Missouri. Over the past few years, the rain has become increasingly scarce due to repeated droughts.
Whenever the crop doesn’t get enough water, it “sweats” through evapotranspiration, drawing water from the ground through its roots. The water then travels through their stems and leaves before it’s released into the air as water vapor. The process contributes to the high amounts of humidity that agricultural communities sometimes experience during the summer.
“[Corn sweat]is very localized,” Missouri State Climatologist Zack Leasor previously told 5 On Your Side. “There’s a two-month period from late June to early August when corn is really maturing and moving a tremendous amount of water from the soil and releasing what’s left to the atmosphere.”
The corn sweat phenomenon is forecast to be even more intense in 2025 as corn fields are forecast to spread. Missouri’s corn growers are set to plant 3.80 million acres this year, a 10% increase from 2024, according to Missouri Ag Connection. The increase in acres will likely increase corn sweat as well, depending on rainfall.