CoCoRaHS

CoCoRaHS (Community Collaborative Rain, Hail & Snow Network) is a grassroots volunteer network that gathers local precipitation observations across North America. People of all ages and backgrounds measure rain, hail, and snow in their communities, helping show how weather can vary from one neighborhood to another. With more than 28,000 active observers across the United States, Canada, Puerto Rico, the U.S. Virgin Islands, Guam, and the Bahamas, CoCoRaHS is the largest source of daily precipitation observations in North America.

The network uses low-cost measurement tools, supported by training and educational resources, to produce data for natural resource management, education, and research. Its website and mobile app allow observers to submit measurements and view observations mapped in near real time, while data users can explore precipitation information. CoCoRaHS offers volunteer sign-up, observer training, instructional materials, webinars, videos, and other weather education resources. Participation is open to anyone with an interest in weather and a willingness to learn; reporting typically takes about five minutes a day.