It’s hot and humid in Minnesota. Is ‘corn sweat’ to blame?

The Twin Cities and much of southern Minnesota are experiencing sweltering temperatures and sticky humidity this week.

Could “corn sweat” be partially to blame?

Corn sweat refers to evapotranspiration — the process by which corn absorbs water from the ground and releases it into the air. That added condensation is likely one factor contributing to the hot, humid weather coming to some parts of Minnesota on Tuesday and Wednesday.

But it’s only part of the reason for this week’s hot and humid weather, said Kenny Blumenfeld, senior climatologist for the Minnesota Department of Natural Resources.

“If the air is blowing off of the Gulf, we’re going to be humid,” he said. “If it’s sunny [locally], you’re going to have a lot of evapotranspiration, or additional humidity coming off the plants.”

The corn sweat effect is largely limited to the peak growing season, which usually happens during the height of the summer, from mid-July to mid-August, he said.

That effect can be particularly noticeable in states like Minnesota, where corn, a water-intensive plant, is the most abundant crop by far.

However, corn isn’t the only plant contributing to humidity.

“You get a lot more from corn,” he said. “But our trees are doing it. Our tall grasses are doing it, our lawn grasses, turf grasses, are doing it. Bushes are doing it.”

Still, the hot topic phenomenon can add about 5 to 10 degrees to the dew point, a measure of the amount of moisture in the air, Blumenfeld said.

Dew points in the upper 60s are uncomfortable, and those that reach into the 70s can be downright oppressive. On Tuesday and Wednesday in some parts of Minnesota, the dew point could stretch as high as the mid-70s.

A high dew point can make hot temperatures even hotter, according to Blumenfeld.