National Weather Service United States Department of Commerce

The NWS Cooperative Observer Program (COOP)


The Hoosier COOP Program


The National Weather Service's Cooperative Observation Program (COOP; pronounced co-op) is one of our federal government's best efforts. Dating back over 130 years, the data from the program has not only defined the climatology of the United States, but has helped us literally build the commerce, infrastructure and well being of our country. Although we are one of the youngest countries on earth, we have arguably the longest and most comprehensive climatology record due to the COOP program.  There are approximately 145 COOP stations in Indiana, 60 of which are in the NWS Indianapolis' 39-county area of responsibility, and 16 of these 60 have over 100 years of service as of September 2021.  The longest serving site is Bloomington Indiana University, having started in 1882!

The National Weather Service (NWS) in Indiana depends heavily on the COOP. The network gathers data for our day-to-day forecasts and warnings, as well as for publication and research. Volunteers from all walks of life observe and report daily maximum and minimum temperatures; 24-hour precipitation amounts, including snowfall and snow depth; soil temperatures; evaporation readings (including miles of wind that has passed over the evaporation tank); and river levels.

Within the network, stations are classified into sub-networks depending on the type of data they collect or how it is used. COOP stations are generally located in either a grid system or just spaced appropriately to fulfill the need required of the different sub-networks. The established sites in the different networks generally preclude expansion, however if the need arises, new stations can be added.

Observers use either an official metal 8-inch diameter standard rain gauge or a plastic 4-inch diameter gauge. During the cold months, 24-hour snowfall and snow depth observations are also taken. Some stations measure precipitation by maintaining an automated electronic gauge known as the Fischer & Porter Rebuild gauge.  Stations that report daily maximum, minimum and “at observation” temperature readings also use official equipment consisting of either the electronic Maximum-Minimum Temperature System (MMTS) or liquid-in-glass thermometers housed in wooden louvered shelters.  New consolidated equipment capable of measuring multiple parameters and transmitting it wirelessly is being explored to replace the currently wired, more expensive, individual, and in some cases no longer manufactured equipment.

Observers leave the program from time to time, requiring replacement observers and the relocation of the stations. Station relocations must be within 5 miles of the original site and have the proper exposure to the elements to collect the needed data. For those lucky enough to become a new observer, a great deal of dedication is required. The observations are needed every day at the prescribed time. Backup observers (relatives, neighbors, or friends) are used as much as possible to avoid any lost days of data, and the MMTS system has the capability of saving 35 days of temperatures to help in this effort.

Stations in the COOP program follow distinct guidelines. Observations at most sites are taken at around 7 AM daily and reported via the Internet using a interface called WX-CODER (pronounced "weather coder"), otherwise by phone to an automated system called IV-ROCS (pronounced "ivy rocks"). Many institutions such as universities, wastewater treatment plants, water companies, and power companies are involved in the cooperative program. Many of these locations are at river sites where consciousness of the river stage is vital to our hydrologic operations.

The bulk of the observers in the COOP program are private citizens who give their time and effort to take an active part in their community. These outstanding individuals vary in professions from bankers and salesmen to homemakers and farmers.

The COOP’s award system recognizes these volunteers with a Length of Service Award every 5 years, starting after the tenth year for individuals (at both homes and institutions), and at every 25-year interval for institutions (awarded to the institution as a whole).

Institutional sites can receive the Honored Institution award for exceptional and extended length of service. For those observers at non-institutional sites who have shown extraordinary service with outstanding observations for extended periods of time, there is the John Campanius Holm award (given to only 25 individuals nationally per year). For those who have received the Holm award and have achieved an exceptional level of service to the program and their community, there is the prestigious Thomas Jefferson award (given to only 5 individuals nationally per year). In Indiana, our longest serving Individual COOP observers were Elwood Kirkwood of Mauzy (near Rushville), who completed nearly 64 years of service from 1881-1944, and Ruth Everhart of Seymour, who completed just short of 64 years and 10 months from November 1947 to September 2012.

History of the Co-op Program


With all of the state-of-the-art technology associated with the modernization of the National Weather Service there remains a program administered by the Weather Service that has changed little since its inception in 1890, the Cooperative Observer Program.  The program has approximately 8,500 volunteer weather observers across the country recording daily temperature and precipitation data. Some also record or report additional information such as soil temperature, evaporation and wind movement, agricultural data, water equivalent of snow on the ground, river stages, lake levels, atmospheric phenomena, and road hazards. Many cooperative stations in the United States have been collecting weather data from the same location for over 100 years.

The first extensive network of cooperative stations was set up in the 1890's as a result of an act of congress in 1890 that established the Weather Bureau, but many of its stations began operation long before that time. John Companius Holm's weather records, taken without the benefit of instruments in 1644 and 1645, were the earliest known observations in the United States. Subsequently many people, including George Washington, Thomas Jefferson, and Benjamin Franklin, maintained weather records. Jefferson maintained an almost unbroken record of weather observations between 1776 and 1816 and Washington took his last weather 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 Climate Network (HCN) and the U.S. Reference Climate Network (CRN).

Equipment to gather the data is provided and maintained by the National Weather Service, and the data gathered is transmitted to the National Centers for Environmental Information (NCEI) in Asheville, North Carolina, where data receives final quality control, online publication, and is archived. Volunteer weather observers regularly and conscientiously contribute their time so that their observations can provide the vital information needed. The data is invaluable in learning more about the floods, droughts, and heat and cold waves which inevitably affect everyone. It also is used in agricultural planning and assessment, engineering, environmental-impact assessment, utilities planning, and litigation and play a critical role in efforts to recognize and evaluate the extent of human impacts on climate from local to global scales. Daily precipitation reports go to River Forecast Centers in support of the National Weather Service hydrology program.