Cooperative Weather Observer Program

The National Weather Service (NWS) Cooperative Observer Program (COOP) is truly the Nation's weather and climate observing network of, by and for the people. More than 11,000 volunteers take observations on farms, in urban and suburban areas, National Parks, seashores, and mountaintops. The data are truly representative of where people live, work and play.

The COOP was formally created in 1890 under the Organic Act. Its mission is two-fold:

  • To provide observational meteorological data, usually consisting of daily maximum and minimum temperatures, snowfall, and 24-hour precipitation totals, required to define the climate of the United States and to help measure long-term climate changes
  • To provide observational meteorological data in near real-time to support forecast, warning and other public service programs of the NWS.

COOP observational data supports the NWS climate program and field operations. The program responsibilities include:

  • Selecting data sites
  • Recruiting, appointing and training of observers
  • Installing and maintaining equipment
  • Keeping station documentation observer payroll
  • Collecting data and its delivering it to users
  • Maintaining data quality control
  • Managing fiscal and human resources required to accomplish program objectives.

A cooperative station is a site where observations are taken or other services rendered by volunteers or contractors. Observers are not required to take any tests. Automatic observing stations are considered cooperative stations if their observed data are used for services which otherwise would be provided by cooperative observers. A cooperative station may be collocated with other types of observing stations such as standard observations stations, Flight Service Stations, etc. In these cases, that portion of the station observing program supporting the cooperative program's mission is treated and documented independently of the other observational and service programs.

While most cooperative observers are volunteers some are paid where specific types of services are needed. Observers frequently record temperature and precipitation daily and send those reports monthly to the National Climatic Data Center (NCDC) or an NWS office. Many cooperative observers provide additional hydrological or meteorological data, such as evaporation. Data is transmitted via telephone, computer or mail. Equipment used at NWS cooperative stations may be owned by the NWS, the observer, or by a company or other government agency, as long as it meets NWS equipment standards.

The first network of cooperative stations was set up as a result of an act of Congress in 1890 that established the Weather Bureau, but many COOP stations began operation long before that time. John Campanius Holm's weather records, taken without the benefit of instruments in 1644-45, were the earliest known observations in the United States. Subsequently many persons, including George Washington, Thomas Jefferson, and Benjamin Franklin, maintained weather records. Thomas Jefferson maintained an almost unbroken record of weather observations between 1776 and 1816, and George Washington took his last observation just a few days before he died.

Two of the most prestigious awards given to Cooperative Weather Observers are named after Holm and Jefferson. Because of its many decades of relatively stable operation, high station density, and high proportion of rural locations, the Cooperative Network has been recognized as the most definitive source of information on U.S. climate trends for temperature and precipitation. Cooperative stations form the core of the U.S. Historical Network (HCN) and the U.S. Reference Climate Network.

Equipment to gather these data is provided and maintained by the NWS. Observers send data forms sent monthly to NCDC in Asheville, NC, where data are digitized, checked and archived.

Volunteer weather observers conscientiously contribute their time so that observations can provide the vital information needed. These data are invaluable in learning more about the floods, droughts, heat and cold waves affecting us all. The data are also used in agricultural planning and assessment, engineering, environmental-impact assessment, utilities planning, and litigation. COOP data plays a critical role in efforts to recognize and evaluate the extent of human impacts on climate from local to global scales.


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