The National Weather Service (NWS) Cooperative Observer Program (COOP) is a network of daily weather observations taken by more than 8,500 volunteers. These data, which include observations from the late 1800’s, are vital to understanding the U.S. climate, and also provide near real-time information that supports forecasts, warnings and alerts, and other public service programs. Observations taken from around the U.S. and its territories at National Parks, seashores, mountaintops, farms, and many urban and suburban areas. COOP data usually consist of daily maximum and minimum temperatures, snowfall, snow depth, and 24-hour precipitation totals. Observations may include additional hydrological or meteorological data such as evaporation or soil temperatures.
NCEI provides free access to digital data through the following access methods. Physical, certified data are also available.
Original COOP Observation Forms
Daily observations provided on handwritten or computer-generated forms. These may include remarks or additional information supplied by the observer. Available one month at a time.
COOP Data with a 24-hour Lag
Data are electronically generated and available for most COOP stations. Data do not include remarks and additional information supplied by the observer. Generally available within 24 hours of observation.
- 15-Minute Precipitation
- Hourly Precipitation
- Global Historical Climatology Network - Daily (GHCND)
GHCN-Daily is the official archived dataset. It includes data from legacy NCEI-maintained legacy datasets with daily temporal resolution (i.e., DSI 3200, DSI 3201, DSI 3202, DSI 3205, DSI 3206, DSI 3208, DSI 3210, etc.).