CoCoRaHS, short for the Community Collaborative Rain, Hail, and Snow Network, is a nonprofit, community-based network of trained volunteers who use affordable tools to measure weather and collect high-quality data to support research and education. 

The network started at the Colorado Climate Center at Colorado State University in 1998 after the Fort Collins flood. Since then, it has grown to cover all fifty states, with thousands of volunteers in the Northern Hemisphere. 

The project is inclusive, welcoming anyone with enthusiasm for tracking the weather and a curiosity to learn more about its effects.

Volunteers measure how much precipitation falls in their area daily using simple tools and then record their findings on the CoCoRaHS website. This data then helps a wide range of people and organizations, from the National Weather Service to local farmers and even neighbors curious about the rainfall in their area.

CoCoRaHS has a few key goals: to provide accurate and timely precipitation data, to increase the amount of weather data collected by encouraging more people to volunteer, to make learning about meteorology fun, and to offer educational resources on water and weather for teachers and the community.

The project has received support from the National Oceanic and Atmospheric Administration, the National Science Foundation, and various other organizations that have helped with funding, supplies, and equipment.

By joining CoCoRaHS, volunteers help their community and others understand and manage weather impacts. 

To learn more, visit CoCoRaHS. To join the network in the U.S., visit Become a CoCoRaHS Observer.