National Weather Service United States Department of Commerce
COOP Program


Perspective of the program
What is a cooperative observer?
What equipment is used?
What happens with the information collected daily?
What kind of training is involved?


National Weather Service Cooperative Observer - A perspective  Up Arrow

The National Weather Service (NWS) has been tasked with the issuance of severe weather watches and warnings designed to protect life and property. To this end, the collection of timely and accurate surface weather data is vital. In addition to the protection of life and property, the Department of Commerce's National Oceanic and Atmospheric Administration (of which the NWS is a part) has been given the job of maintaining a database of climatic weather information. This too is used by the NWS in preparing medium and long range forecasts.

These two jobs have the Cooperative Observer Program, Co-Op Program in short, in common. The Co-Op Program is the backbone of the United States Climatological database. Co-Op observers frequently act as both as severe storm spotters, phoning in reports of hazardous weather in the winter and summer.

What is the job of a cooperative observer? Up arrow

Being a NWS cooperative observer can be a demanding job. To provide accurate and complete weather data, observations are required seven days a week 365 days a year, and at the same time each day for consistency. This does not mean that someone has to be monitoring the weather all the time; instruments are provided to monitor precipitation and/or temperature. The recording of data at most cooperative sites is around 7am.

This information is recorded on a form, which is mailed monthly to the local NWS office for quality assurance before forwarding to the National Climatic Data Center (NCDC) in Asheville, North Carolina. However, efforts are ongoing to transition to a paperless web based data entry system.

There is also a secondary level of cooperative observing, the unofficial coop. No less important that the official coop sites, unofficial coop observers provide valuable information on precipitation to the NWS. The only real difference between official and unofficial coops is the unofficial coop data are not archived on a national level. Unofficial coops typically receive just a plastic 4 inch rain gage.


What equipment is used? Up arrow

All equipment (such as a rain gauge) and supplies (forms, envelopes, etc) are provided by the National Weather Service. 
standard 8-inch rain gaugeDepending on the level of service expected, equipment can vary from a simple 4 inch non recording plastic gage or an 8 inch metal rain gauge, to a full coop station with electronic thermometer and recording precipitation gauge. The placement and type of Cooperative Weather Observers is determined by the NCDC as requested by the NWS Representative (NWSREP). Generally cooperative stations are evenly spaced in relatively flat terrain (more than 30 miles apart) but may be closer together in hilly terrain or under special circumstances. Most common are the "B" order stations which support hydrological programs as well as climatological programs. Typically these are observers have a non recording rain gage. "A" and "B" order stations are for longer term climatological and hydrologic operations.

The NWSREP will deliver, set up, and maintain the necessary equipment. Typically, a station consists of a set of Maximum/Minimum thermometers or a Max/Min Temperature System (MMTS) and a rain gauge. There are two basic types of rain gauges - recording and non-recording. Non-recording rain gauges consist of a metal tube approximately 8 inches in diameter and 3 feet tall with a removable Max Min Temperature Systemfunnel and inner plastic or metal measuring tube. Precipitation is measured by placing a calibrated stick into the tube, seeing where the water marks the stick and recording the data.

A recording rain gauge has either a drum which holds a paper chart or a drive mechanism which punches holes in a strip chart to record precipitation. At the end of each month, the charts are forwarded to the local NWS office for QA then forwarding to NCDC.

Other equipment used may include soil thermometers, evaporation pans, and hygrothermometers.


What happens with the information collected daily? Up arrow

Most sites transmit data using WxCoder. WxCoder is a web-based data entry system that allows climate observers in the National Weather Service Cooperative Network program to enter daily observations for near real-time reporting and for official entry into NOAA’s National Climatic Data Center (NCDC). This near real-time data is used to support the day-to-day operations of the NWS in its forecast and warning decisions, and various other users such as state climatologists. Daily precipitation (rain and snow) reports are important inputs to NWS river forecast models used in river flood warning operations.


What kind of training is involved? Up arrow

Training consists of on site, hands on instruction with the designated cooperative observer and their backup. This usually is done the same day as the equipment is installed and takes about one hour. Basic equipment maintenance is discussed and the cooperative observer is provided with a name ("point of contact") and a number should additional questions or problems arise. A reference binder is also provided.

Where there is a need for an observer for a particular location, a notice will be posted on our webpage.