Corn Sweat Midwest Humidity: As temperatures climb and summer days grow longer in the Upper Midwest, residents brace for the annual heat waves and the heavy humidity that often accompanies them. This year, a lesser-known phenomenon has captured the public’s attention: “corn sweat.” While it may sound like a whimsical term, its effects are anything but lighthearted. The sticky, humid conditions that have been plaguing the Midwest might have more to do with the vast fields of corn than anyone initially thought.
Understanding Corn Sweat: The Science Behind the Stickiness
Corn sweat, a colloquial term for a process called evapotranspiration, refers to the way corn and other plants release moisture into the air. Unlike human perspiration, where sweat is evaporated from the skin to cool the body, corn sweat is the result of water vapor released by plants. Trenton Ford, Illinois State Climatologist, explains, “Using the term ‘corn sweat’ is kind of funny. It’s not perfect as with most metaphors. Humans and a few other animals will perspire when we get hot, and sweat is evaporated off our skin. What corn does is a bit of a different process.”
Evapotranspiration involves plants taking in water through their roots, transporting it through their tissues, and then releasing water vapor into the atmosphere. This process is crucial for the plant’s health, as it helps in the transport of nutrients from the soil to the leaves, where photosynthesis occurs. The end result is the release of moisture into the air, which can significantly impact local humidity levels, especially when considering the sheer volume of crops grown in the Midwest.
Why Does the Midwest Feel Extra Humid During the Summer?
The Midwest is known for its vast expanses of cornfields. In 2024, farmers planted a staggering 91.5 million acres of corn across the United States, with a significant portion of these fields concentrated in the Midwest. According to the U.S. Geological Survey, a single acre of corn can release between 3,000 to 4,000 gallons of water into the atmosphere each day during the growing season. This immense amount of moisture contributes heavily to the region’s already high humidity levels, making the summer heat feel even more oppressive.
Bruno Basso, a crop and agriculture scientist at Michigan State University, contrasts modern cornfields with the natural prairie ecosystems that once dominated the Great Plains. “Native prairies are diverse ecosystems with a variety of plant species, each with different root depths and water needs, helping to create a balanced moisture cycle,” Basso explains. “In contrast, corn and soy monocultures are uniform and can draw water from the soil more quickly.” This uniformity results in a much higher rate of water vapor being released into the atmosphere, contributing to increased humidity.
The Impact of Corn Sweat on Heat and Health
High humidity levels can exacerbate the health risks associated with extreme heat. When the air is thick with moisture, it becomes harder for sweat to evaporate from the skin, which is a critical mechanism for cooling the human body. Ashton Robinson Cook, a meteorologist and forecaster at the National Weather Service’s Weather Prediction Center, notes that higher humidity levels can trap heat, especially overnight, preventing temperatures from dropping and leading to prolonged heat stress. “When there’s little relief overnight, there’s more heat stress,” Cook adds.
This is particularly concerning given that extreme heat is the leading cause of weather-related deaths in the United States. The added moisture from corn sweat can make heat waves more dangerous by intensifying the effects of heat on the body, especially for vulnerable populations such as the elderly, young children, and those with pre-existing health conditions.
How Much Does Corn Sweat Contribute to Humidity?
While it’s clear that corn sweat contributes to the Midwest’s humidity, the exact extent of its impact is still under study. A study from 2011 found that Midwestern crops, primarily corn, increased humidity by about 40% during a heat wave. However, scientists like Trenton Ford caution that there’s still much to learn about this phenomenon. “There’s a common assumption among folks who aren’t in the weather community that we can measure everything, and are measuring everything,” Ford states. “That’s just not the case.”
Future research, particularly with the use of remote sensing satellites, could provide more detailed insights into how much corn sweat contributes to regional humidity levels. Understanding this relationship is crucial for developing better predictive models for weather patterns and heat-related health risks.
The Silver Lining: Corn Sweat as an Indicator of Healthy Crops
Despite the discomfort and health risks associated with increased humidity, corn sweat also signals a positive aspect for farmers: it’s a sign of healthy crops. Meaghan Anderson, an educator and field agronomist with Iowa State University Extension and Outreach, highlights that “a lot of transpiration and humidity is a good thing for crops because it means there’s moisture available in the soil, the crops are successfully photosynthesizing. They’re doing what they need to do to produce yield at the end of the season.”
For the agricultural community, the presence of corn sweat indicates that the plants are actively growing and that the conditions are favorable for a good harvest. This is vital for a region that relies heavily on agriculture as a cornerstone of its economy.
Conclusion: Navigating the Humid Summers of the Midwest
As we endure another sweltering summer in the Midwest, it’s clear that corn sweat plays a significant role in the region’s climate. While it adds to the discomfort of those hot, sticky days, it’s also an essential part of the agricultural cycle that supports the region’s economy. As climate change continues to affect weather patterns, understanding phenomena like corn sweat becomes increasingly important.
As residents of the Midwest, it’s essential to stay informed and prepared for the effects of high humidity and heat. Whether it’s through staying hydrated, seeking shade, or simply being aware of the weather forecasts, knowledge is the best tool we have to navigate these sticky summer days.
So next time you feel that thick, heavy air while walking past a cornfield, remember—it’s not just the sun that’s making you sweat; it’s the corn too.
