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Good to the last drop: an introduction to CoCoRaHS precipitation reporting

by Wyoming Livestock Roundup

The short days, long nights and cold temperatures this time of year can be difficult for folks who enjoy keeping an eye on hayfields, pastures, lawns and gardens during warmer months.

It can feel like our winter interactions with natural resources in our environment are limited to scooping snow out of the driveway and keeping livestock fed. Winter in Wyoming can be isolating. 

It can also be the perfect time to build a new habit and reconnect with nature and other people, while making a difference in the community. 

The Community Collaborative Rain, Hail and Snow Network, fondly known by its acronym CoCoRaHS, is a network of independent citizen-scientists who report daily precipitation totals to supplement data collected by the National Weather Service. 

Active reporting takes place in all 50 states plus Puerto Rico, the U.S. Virgin Islands, Guam, Canada and the Bahamas. Wyoming has been a participating state since 2003. The full origin story of CoCoRaHS can be found at

All participants

Reporting for CoCoRaHS does not require any formal education or prior experience. There are brief training modules available on the CoCoRaHS website and on YouTube, including an intro video, which can be found at 

Participation in a comprehensive, hour-long introductory training session is strongly encouraged when initiating a new reporting site. 

This activity is well-suited for people of all ages and walks of life. For schoolchildren, CoCoRaHS reporting can be good practice for making observations and engaging with the natural world. It provides an enrichment opportunity for those living in retirement and senior communities. 

Many agricultural producers are already tracking their local rain and snow events, and CoCoRaHS is an easy way to digitize and archive measurements for later reference. 

How it works

The necessary supplies are simple – a four-inch standardized rain gauge, a clear place to mount it away from obstructions, a free CoCoRaHS online account and a decent internet connection. 

There are numerous instructional videos and guides available online that outline reporting procedures. 

Basically, at a consistent time each day, an observer reads their rain gauge, enters their measurement into their daily report using their CoCoRaHS account online or via the CoCoRaHS smartphone app and then empties any collected moisture from the gauge so it is ready for the next 24-hour period. 

Note, zero values are just as important, if not more, to report as measured precipitation. If a person has experienced three months with no precipitation, CoCoRaHS followers want to know.

It gets a little more complicated when there is snow involved, but the fundamental process remains the same. Since snow varies in water content, it takes a few extra steps to measure the actual amount of water in a given volume of snow. 

The CoCoRaHS team has created several resources to help make the process easy. A YouTube video, which can be found at describes how to measure snow.

There is also an option to enter a multi-day report for instances when an individual is unavailable for a few days.

This has worked well for me since the gauge I report for is located at the Johnson County Extension office in Buffalo, and I don’t tend to check it over the weekends. When I travel during the week, I use a multi-day report to make sure no days go unaccounted for.

Why it matters

The CoCoRaHS program is the result of a flooding event along the front range of Colorado, which was not anticipated by the weather service. Rain fell heavily in some places but it did not at the location of the official weather station in Fort Collins, Colo. so officials were unaware of the threat of flooding. 

This incident raised awareness of how highly variable precipitation can be, even among locations less than half a mile apart. CoCoRaHS reporting helps fine-tune the understanding of storm profiles, and the more reports submitted, the clearer the picture becomes.

Participating allows individuals to keep a record of their local conditions and benefits the community at large.

State meteorologists use CoCoRaHS data to anticipate severe weather events, as the network was originally intended. 

CoCoRaHS data is also used by climatologists to develop the Wyoming drought monitor map, and to track snowpack, which provides irrigation and drinking water to much of the Intermountain West. 

This data informs decisions made by state and local governments, which have direct impacts on those who depend on water for their livelihoods – think agriculturalists, recreational, fishing and hunting outfitters and all of the businesses benefiting from regional tourism to lakes, ponds, reservoirs, rivers and streams.

How to get started

The first step to getting started is to collect required supplies. The CoCoRaHS online store, found at, has a list of available options. 

Next, individuals need to mount their official CoCoRaHS gauge in a site away from obstructions like houses and trees.

Third, they should register their new reporting site at If individuals have questions or are interested in attending a training session, they should connect with Wyoming CoCoRaHS Coordinator Tony Bergantino by e-mailing or calling 307-766-3786.

Lastly, individuals can begin reporting daily precipitation totals, knowing they are making a difference.


The CoCoRaHS is a grassroots effort by citizen scientists to measure precipitation and improve weather and climate scientists’ ability to anticipate severe weather. The water data collected informs governmental policy at several levels, which has a direct impact on agriculture and other industries depending on this critical natural resource. 

Participating in CoCoRaHS reporting is a simple to way to become more mindful of local weather, connect with the natural environment and to benefit the community.

Micah Most is an agriculture and natural resources educator with University of Wyoming Johnson County Extension. He can be reached at or 307-684-7522.

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