Did you know corn can make a summer day more humid? WAVE 3 meteorologist Tawana Andrew breaks it down for us.
Bill Burton: It's time for us to take a look at the Science Behind the Forecast, as I am joined by WAVE 3 meteorologist Tawana Andrew. Good morning, Tawana.
Tawana Andrew: Good morning. Right now we're going to talk about one of, what I think is one of the hottest topics on the internet, and I literally this is what everybody's talking about right now, for some reason.
BB: It's the absolute hit of the summer, and it has nothing to do with Sabrina Carpenter. We are going to be talking about corn sweat. That's the hit of the summer. Tell us about it.
TA: Yes. So corn sweat references the amount of moisture that corn crops release into the atmosphere. But corn is not the only plant that sweats. Basically, it's just evapotranspiration, and that is the process of water transferring into the atmosphere through evaporation and transpiration. So we learned about evaporation in elementary school. That occurs when liquid water becomes a gas or water vapor. And during transpiration, plants absorb water from the soil, and then they will release it as water vapor into the atmosphere through their leaves. So every single plant does this, there's a couple of factors that impact transpiration. First, the type of plant is very important. So is soil type, soil saturation, any recent precipitation, solar radiation or relative humidity, wind temperature, and even the slope of the land can impact transpiration. So there's a lot of factors to keep in mind. So certain plants, like cacti and other desert species, don't really release a lot of water into the atmosphere. But diving into the numbers, yeah, this, this is where we're gonna get a little bit fun right now.
BB: OK, I'm ready.
TA: So the U.S. Geological Survey says that an acre of corn releases about 3,000 to 4,000 gallons of water every day.
BB: That's some sweaty corn!
TA: That's a lot of water. Now the data shows that there is 91.5 million acres of corn that were planted in the U.S. in 2024. OK, so I'm a nerd, so that means I did the math, and that equates to 274.5 billion to 336 billion gallons of water being released into the air by corn crops every single day across the country.
BB: I can't even wrap my head around that.
TA: I can't either. That's a lot of swimming pools. So in comparison to the 3,000 to 40,00 gallons of water being released by corn every day, an oak tree — a large oak tree — transpires about 109 gallons of water every day,
BB: A bit of a difference.
TA: Just a little, just a little. So for transpiration, that will actually decrease as humidity increases. So with the air already incredibly saturated, filled with moisture, it's hard to add more moisture to something that's already filled. So that's why you don't really have that transpiration going on as much on a very humid day. But transpiration will increase as temperatures go up, because hotter temperatures open up a plant stoma. So that's where water vapor is released, while colder temperatures will shut it down.
