Community Collaborative Rain, Hail and Snow network

CoCoRaHS Homepage

Daily Virginia Precipitation Plot

Daily North Carolina Precipitation Plot

Daily Maryland Precipitation Plot

What is CoCoRaHS?

CoCoRaHS stands for the Community Collaborative Rain, Hail & Snow network. It is a unique, non-profit, community-based network of volunteers of all ages and backgrounds working together to measure and map precipitation (rain, snow and hail). The network originated with the Colorado Climate Center at Colorado State University in 1998 thanks in part to a devastating flood that occurred in the previous year. Since then, the network has expanded rapidly with over 6,500+ observers in 26 states. 

Can I participate?

Absolutely! The ultimate goal of the program is to have one observer per square mile in urban/suburban areas and one observer every 36 square miles in rural areas. Everyone can help; young, old, and in-between. The only requirements are an enthusiasm for watching and reporting weather conditions and a desire to learn more about how weather can effect and impact our lives. Quite a few schools have folded CoCoRaHS into their Science curriculum, with students taking and reporting rainfall measurements everyday as part of a year-long science project!

 Once trained, volunteers collect data using low cost measuring tools such as a 4-inch diameter high capacity rain gage (pictured right), snow boards to measure snow, and aluminum foil-wrapped Styrofoam hail pads. Information on purchasing a modestly priced rain gage can be found via the CoCoRaHS main page. 
4 inch Diameter High Capacity Rain Gage

How does it work ?

Each time a rain, or snow storm crosses your area, and every time hail is reported, volunteers take measurements of precipitation from as many locations as possible.  These precipitation reports are then recorded on the CoCoRaHS web site, The data are then displayed and organized for many of our end users to analyze and apply to daily situations ranging from water resource analysis and severe storm warnings to neighbors comparing how much rain fell in their backyards.

CoCoRaHS has several goals. 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..

Click Here to Join CoCoRaHS!

How do I join?

Either click on the “Join CoCoRaHS” image to the right, visit the CoCoRaHS home page at Any questions about the program can also be directed to the Regional Coordiator, Mike Montefusco at