CoCoRaHS — Community Collaborative Rain, Hail and Snow Network: Citizen Scientists Track Precipitation

Federal Crowdsourcing and Citizen Science Toolkit

Co-sponsored by the National Oceanic and Atmospheric Administration and the National Science Foundation, CoCoRaHS is for citizen scientists of all ages and from all walks of life who can spend a few minutes per day collecting information on precipitation in their area. Volunteers register their location on the project website and can train themselves online or in person with a local coordinator. By following a set of simple procedures and using a standardized rain gauge, volunteers measure and report their daily amount of rain (or melted snow) on the project website, making the data readily available in a centralized database at the touch of a fingertip. Options to report hail and/or other kinds of weather are also available, as well as advanced options such as evapotranspiration and drought impact reports.

From its origins in Colorado, word of CoCoRaHS spread, and scientists began requesting support for data collection across the United States. CoCoRaHS responded by offering newly participating states access to its technological platform but requiring each state to establish its own network of volunteer leaders responsible for recruiting, training and retaining local monitors. Motivated local leaders have helped expand CoCoRaHS to more than 20,000 active volunteers in all 50 states as well as Washington, D.C. (including the White House!), Puerto Rico, the U.S. Virgin Islands and most provinces in Canada.

A full case study of CoCoRaHS is located in the Federal Crowdsourcing and Citizen Science Toolkit,

CoCoRaHS Short


CoCoRaHS has several goals (as stated in their mission statement).

1) provide accurate high-quality precipitation data for our many end users on a timely basis;

2) increasing the density of precipitation data available throughout the country by encouraging volunteer weather observing;

3) encouraging citizens to have fun participating in meteorological science and heightening their awareness about weather;

4) providing enrichment activities in water and weather resources for teachers, educators and the community at large to name a few.

High Level Impact: 

Observations made by volunteers are immediately available for public use on maps and in reports. By providing high-quality, accurate measurements, project participants supplement existing networks and provide useful data to scientists, resource managers, decision makers and others — all at a very modest cost.

Point of Contact: 

National Coordinator - Henry Reges (970) 491-1196,

Education/Schools - Noah Newman (970) 491-8545,

For station and web site related questions, e-mail,

Contact CoCoRaHS national director, Nolan Doesken at with suggestions, questions, or comments.