Community Collaborative Rain, Hail and Snow Network
The Community Collaborative Rain, Hail and Snow Network, or CoCoRaHS, is a network of volunteer weather observers in the United States, Canada, and the Bahamas that take daily readings of precipitation and report them to a central data store over the Internet. The program is an example of citizen science.
Source: Wikipedia — Community Collaborative Rain, Hail and Snow Network (CC BY-SA 4.0)