Editor’s note: The Farm Progress Show is Aug. 27-29 in Boone, Iowa. Visit FarmProgressShow.com.

by Chris Kick

Most of us know how to use a rain gauge, or at least most of us think that we know how. Set it outdoors before a rainfall, check it after the storm has passed, and then tell your friends and neighbors how much rain fell.

If you want to get an “accurate” measurement of precipitation, though, you probably need to do a little more work.

Use rain gauge correctly

Madelynn Wuestenberg, agricultural climatology specialist with Iowa State University Extension and Outreach, will explain the best practices for selecting and using a rain gauge at this year’s Farm Progress Show.

As it turns out, there can be much variability from one gauge to another. Factors such as diameter, length and placement can all significantly impact measurement accuracy.

Wuestenberg’s display will include various kinds of rain gauges, and she will test participants’ knowledge of how to read them. She will also explain how an automated rain gauge works. It’s a more sophisticated device, which automatically sends data to a data logger. This type of rain gauge helps measure total rainfall, as well as rainfall frequency and intensity.

“I will be highlighting how people can become weather reporters, and how to correctly read a rain gauge,” Wuestenberg says. “We need citizen-scientists to help improve weather predictions, and we need to empower individuals that they have the capacity and knowledge to record weather data.”

Community network

Wuestenberg will give special attention to how rain gauges are used for the Community Collaborative Rain, Hail and Snow Network.

The CoCoRaHS program began in 1987. It encourages the use of low-cost measurement tools used by trained individuals with the goal of providing high-quality data for natural resources, education and research initiatives.

The data from CoCoRaHS participants is publicly available and is shown on the program’s online mapping system.

“These are ‘citizen-scientists’ who are providing important data that is used to inform and validate weather data, education and drought monitoring,” Wuestenberg says. “The program empowers individuals to have the capacity and the knowledge to gather this data, and make accurate assessments about their own precipitation.”

Today, more than 26,000 active precipitation observers record their data in the United States, Canada, Puerto Rico, the U.S. Virgin Islands, Guam, and the Bahamas.

170 participate so far in Iowa

Iowa has about 170 active participants on record, and Wuestenberg hopes to expand that number.

One contributor is Mark Licht, cropping systems specialist with ISU Extension. He will be on hand at the show to discuss how to take good measurements and what the information means for farmers.

“I will be able to explain not only how to collect rainfall totals, but also speak about the importance of rainfall for crop production,” he says.

The climate exhibit space will also include a pushpin map of the Midwest for people to pinpoint where they live. By doing so, Wuestenberg hopes to bring attention to areas where CoCoRaHS participants are active — and where more are still needed.

“If you live somewhere where there is a significant gap in reporting, we could really use you as a reporter through CoCoRaHS,” Wuestenberg says.

The ISU exhibit space at the show can be found at the corner of Seventh Street and Central Avenue.

Wuestenberg can be reached at 515-294-6014 or [email protected].

Kick is a communication specialist at Iowa State University Extension.