Weather Forecast


Weather Talk: Corn and beans increase the humidity

Probably since the end of the last glaciation 12,000 years ago, the weather has managed to get humid here in the northern Plains at least a few days each summer.

We don’t make the humidity here; we import most of it. The source region for our stickiest air in summer is, of course, the Gulf of Mexico. But robust crops of corn and soybeans throughout the Midwest can add a little more sweat to the mix.

Transpiration processes within green plants add humidity to the air. Fields of beans and corn are more effective than native prairie grasses. And the more robust the beans are, the more humidity they produce.

Evaporation of moisture in the soil adds to the humidity also. But consider that at our most humid, the summer air can be a few degrees of dew point higher than in Florida.

Most of the humidity, to be sure, comes from the Gulf. But the crops between there and here do add a small percentage.

John Wheeler

John was born in Baton Rouge, LA, and grew up near Birmingham, Alabama. As a teenager, his family moved to Madison, Wisconsin, and later to a small town in northeast Iowa. John traces his early interest in weather to the difference in climate between Alabama and Wisconsin. He is a graduate of Iowa State University with a degree in meteorology. Like any meteorologist, John is intrigued by extremes of weather, especially arctic air outbreaks and winter storms.  John has been known to say he prefers his summers to be hot but in winter, he prefers the cold.  When away from work, John enjoys long-distance running and reading.  John has been a meteorologist at WDAY since May of 1985.

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