While some people can smell the arrival of rain or snow, people in the coming days will be smelling corn in the air –and it’s all related to an impressive heat wave due to impact a large part of the country. The high heat is arriving right before corn is harvested, leaving full plump ears of corn on their stalks.  With heat and mature corn growth coming at the same time, a phenomena known as corn sweat will occur.

Corn plants absorb water through their roots, bringing moisture up their stalk into leaves and ears. With the plants maxing out on their water content and high heat imminent, water vapor is released by the corn plants into the atmosphere.  Known as the process of evapotranspiration, this natural process will contribute to increased humidity, especially in regions with large cornfields like the Midwest, where it can significantly impact local weather conditions. Locally, the  vast cornfields of the Midwest are a prime example of where this phenomenon is most noticeable, leading to higher humidity and heat index values.

While the term “corn sweat” is colloquial, it accurately describes a real and measurable effect on the atmosphere. And in addition to adding moisture to the air, it also releases the flavors associated with the corn into the humid airmass too which can blow well down-stream of corn crop fields.

Due to the corn “flavored” evapotranspiration, people even far from corn fields may notice the air has a sweet, corny scent to it, much like what a fresh corn on the cob smells like before you take a bite into it.

As the corn is harvested and as temperatures fall, the evapotranspiration process comes to an end which also ends the process that adds the aroma of corn to the air.