National Weather Service United States Department of Commerce



co-operative observing station graphic


The COOP (Cooperative Observing Program) is a nationwide weather and climate monitoring network of over 8,700 volunteer citizens and institutions observing and reporting weather information on a daily basis. COOP observations form the backbone of temperature and precipitation records describing U.S. climate since the late 1890's. 


To the left, an example of an Arizona COOP observing station is provided. The small white shelter box houses the instrumentation, such as the maximum and minimum thermometers. The cylinder to the left of the shelter box is the rain gauge.


COOP MISSION:  To provide observational meteorological data required to define the climate of the United States and help measure long term climate change. And to provide meteorological data in near real time to support forecast, warning, and other public service programs of the NWS. 

Observations taken by COOP observers generally include the following parameters: 1) 24-hour maximum and minimum temperatures, 2) 24-hour liquid precipitation amounts, and 3) snowfall (and in some cases snow depth).

COOP observers are dedicated individuals who volunteer their time to help further the mission of the National Weather Service. They can be private citizens, or members of a public or private business or institution, such as a water plant, state park, fire department, or radio station. In the Phoenix county warning area, the following table lists our current COOP observers, with the first column indicating the city, and the second the affiliation. If you wish to become a Cooperative Observer, or to learn more about the program, contact our COOP Program Manager, Marvin Percha


Alamo Dam State Park
Bartett Lake Salt River Project
Carefree Airport
Casa Grande Radio Station
Chiriaco Summit Private Citizen
Eagle Mountain Water Pump Plant
East Mesa Private Citizen
El Centro Water Treatment Plant
Eloy Private Citizen
Fountain Hills Parks and Recreation Dept.
Globe Private Citizen
Imperial Irrigation District
Lost Dutchman/Apache Junction State Park
Mormon Flat Dam Salt River Project
Parker Radio Station
Pinnacle Peak Scottsdale City Park
Roosevelt Private Citizen
Stewart Mountain Dam Salt River Project
Tacna Tacna Farm Management
Tempe University
Wittmann Private Citizen
Youngtown City of Youngtown
Yuma State Park