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Is the reason the Midwest is so humid in the summer really due to "corn sweat"?

"Corn Sweat" explained
Is the reason the Midwest is so humid in the summer really due to "corn sweat"?
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From the "Polar Vortex" to the "Bomb Cyclone", these meteorological buzzwords are picked up by the news media and spread around. Now its the latest, and you have probably seen headlines using the phrase "corn sweat" in recent weeks. It sounds silly at first, how can corn sweat? And how does it contribute to our humidity?

So, let's break it down. What is corn sweat, how does it factor into our humidity, and is it overhyped?

Humidity is the amount of water in the air. Most of our humidity (even in the Midwest) comes from various bodies of water, mostly the Gulf, but the Pacific Ocean and even the rivers contribute some too. Yet, there are other small-scale factors that contribute to it too. One of those is corn.

If you get this question on a trivia game, the answer you would be looking for is "evapotranspiration," which is a mash-up of the words "evaporation" and "transpiration." Like humans, plants need to expel water too, so they "sweat" it out.

Corn effectively acts like a giant straw, where it sucks the water from the ground, uses it in photosynthesis, and then emits it into the atmosphere.

On average, 1 acre of corn can emit 3,000 to 4,000 gallons of water per day into the air.

Considering Nebraska has roughly 10,000,000 acres of corn (Iowa 12,600,000), this means that *per day* Nebraska corn emits 30 to 40,000,000,000 (billion) gallons of water! For Iowa, it's even higher!

While this sounds like a lot, it is important to note that "corn sweat" only adds to our humidity in smaller increments than bodies of water (even though Nebraska is the most landlocked state in the country).

However, that small amount does make a difference. In a region well-removed from water sources, humidity should be lower than in the southern US. Yet, with the corn sweat added in, often our humidity levels are on par with the South!