Nationwide volunteer program recruits backyard weather observers

Rainfall totals as reported by Coastal Georgia CoCoRahs volunteers on July 8, 2025. Credit: CoCoRahs

Attention weather nerds. A nationwide volunteer program wants to recruit you to be part of it network of weather observers. 

The Community Collaborative Rain, Hail & Snow Network or CoCoRahs (pronounced KO-ko-rozz) is a grassroots volunteer network of backyard weather observers who measure and map precipitation (rain, hail and snow) daily. 

It has more than 25,000 active volunteers, but it’s always looking for more.

“What’s really great about the network is it kind of fills in the puzzle pieces of where we don’t have automated sensors already,” said Emily McGraw, a meteorologist with the National Weather Service in Charleston who helps coordinate CoCoRahs volunteers. “So it really helps us get the ground truth, versus the radar estimates of precipitation. And then definitely after the events, we can really see the spread of precipitation across the area.”

The CoCoRaHS network was formed in 1998 after storms in the Fort Collins, Colorado area produced heavy but isolated rainfall, up to a foot of rain in some areas but just 2 inches nearby. Several people died in the resulting floods. As the Colorado Climate Center documented the storm, it relied on reports from private citizens with rain gauges. The network grew from there, garnering support from the National Weather Service. 

Michael Moody is one of more than 250 CoCoRahs volunteers in Georgia. Moody lives mainly in Oglethorpe County, where he regularly reports rainfall. “I’ve got something like 5,000 reports so far,” he said. But he’s a part-time resident of Darien, too. He’s not there often enough to collect rainfall data, but he’d love to see more Coastal Georgia residents participate.

A recent CoCoRahs map shows at least one report from all the Coastal Georgia counties, with the most volunteers reporting from Chatham County.

Volunteers report totals from their rain gauges daily. This gauge, in front of The Current office in Savannah is not CoCoRahs-approved. Credit:Mary Landers/The Current

Moody runs a canoe and kayak business on the Broad River, which is not typically high flow. Rainfall upstream helps him predict paddling conditions, both for customers and for himself. 

“I’ve been a canoe and kayaker for more than my adult life,” he said. “And so because I can look up in North Carolina, let’s say, I’m going to paddle some of these streams, and I’ll say, ‘Oh, they’ve had rain, or oops, they haven’t had any rain. Well, screw that, I’m not going to go.'”

It takes Moody 5-10 minutes a day to read his rain gauge and log the measurement into the CoCoRahs site on his computer. 

“I mean, it doesn’t take any time at all,” he said.

Volunteers can report directly through the website, or use an app. 

“You can download the app on your smartphone and report it that way,” McGraw said. “And they recently updated the app, so it’s very user-friendly and easy to use.”

Volunteers typically log in their rainfall measurements between 6 and 9 a.m. It’s OK to miss days.

“The more you report, the better,” said McGraw. “But also you can do multi-day reports. If you happen to go out of town or vacation, you can take your reading in your rain gauge all through the time that you were gone. So you could do a seven-day total if you’re gone for a week.”

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