Providing real-time weather information for growers

Jeff Andresen, a professor in the Michigan State University Department of Geography, Environment and Spatial Sciences and the state climatologist for Michigan, examines weather and its effect on agriculture.

MSU researcher Jeff Andresen at an Enviroweather station.
MSU researcher Jeff Andresen at an Enviroweather station.

It’s no secret the climate is trending warmer all over the world. According to NASA’s Goddard Institute for Space Studies, the planet has experienced 19 of the 20 warmest years on record since 2001, with the only exception being 1998. But what does that mean for day-to-day weather, particularly as it relates to Michigan agriculture?

Jeff Andresen, a professor in the Michigan State University Department of Geography, Environment and Spatial Sciences and the state climatologist for Michigan, examines weather and its effect on agriculture. His research centers on the conditions that cause plant pathogens to thrive, with the goal of helping growers make informed decisions to mitigate damage.

Andresen said Michigan is 2 degrees Fahrenheit warmer, on average, than 50 years ago. The Midwest also receives 10% to 15% more precipitation annually — roughly three to four inches of additional water or the equivalent of a month’s worth of precipitation each year.

Because of the warmer conditions, plants come out of dormancy earlier than usual. Wetter weather has also resulted in plant diseases emerging earlier, causing growers to adjust treatment strategies.

“Plant diseases flourish in wet weather,” Andresen said. “We’re particularly worried about the amount of time that water persists on plant surfaces, which is directly correlated with disease development.”

The amount of water vapor in the air is known as humidity, but what Andresen is more concerned about for fungal diseases is relative humidity — the amount of water vapor in the air compared to how much the air can actually hold. This fluctuates based on temperature. If the relative humidity is high, like on summer mornings in which the temperature is lower, evaporation is not occurring because the air is saturated.

The Michigan tree fruit industry is a longtime partner of Andresen’s, and three of his most studied diseases are apple scab and fire blight, as well as cherry leaf spot. For diseases like these, Andresen said the weather’s unpredictability is the biggest challenge. But his concerns aren’t just with more precipitation equating to more disease issues. It’s also the frequency of rainfall that gives him pause.

“Future projections are all calling for warming,” he said. “It just depends on how much warming. The majority also suggest increases in precipitation, but there’s a catch. Even though there may be more precipitation, it will be more erratic.

“This means we’ll have heavy rain or snow events, followed by extended periods of dryness. It’s a huge potential problem for agriculture, particularly since most of the expected increases in precipitation will occur in the cold season, leaving our growing seasons with long stretches of no rain. That may be good for diseases but bad for overall plant health.”

To get weather information into the hands of growers in a timely fashion, Andresen uses an innovative technology platform called Enviroweather. He serves as director of the system, which provides online information to help users make decisions on diseases, pests and natural resources management.

The Enviroweather network is composed of 100 weather stations, 90 across Michigan and 10 partner stations in Wisconsin. Each station consists of a small tower situated in a strategic area, and compiles data such as air temperature, rainfall, relative humidity, dewpoint and wind direction that is updated online every 30 minutes.

The stations are currently powered by solar panels and batteries that turn on when data needs to be uploaded. Andresen said the stations are being upgraded with larger solar panels and more powerful batteries so they remain on indefinitely, allowing information to be uploaded every five minutes.

“One of the things growers have inquired about is more real-time information,” Andresen said. “By providing new data every five minutes, we’re on par with the National Weather Service. The technology is less expensive than it was even 10 years ago to make these upgrades.

“We’re always looking to add more features and a better user experience — along with more Enviroweather stations — to give growers the opportunity to access critical information near their operations.”

This article was published in Futures, a magazine produced twice per year by Michigan State University AgBioResearch. To view past issues of Futures, visit For more information, email Holly Whetstone, editor, at or call 517-355-0123.

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