The Cooperative observer program was introduced by Thomas Jefferson in 1776. By 1816, he had established a network of volunteer weather observers in every county in the state of Virginia. The network has now grown to over 11,000 stations throughout the United States. Cooperative observer data is used in a variety of ways, including climatology, meteorology, agriculture, aviation and research. The National Weather Service volunteer cooperative observers are an invaluable resource to the nation and should be applauded for their work and dedication.

NWS Sacramento took over a co-op program in early 1995, inheriting stations from neighboring NWS offices in Reno, NV and Monterey, CA. NWS Sacramento has approximately 115 co-op stations recording daily weather information throughout its County Warning Area(CWA), and some beyond it's borders. This large area of varied terrain includes the Sierra Nevada from the northern portion of Yosemite National Park to north of Lassen Volcanic National Park - the San Joaquin and Sacramento Valleys, from Turlock in the south to around Redding in the north - and the east side of the Coastal Ranges from Lake County north to Whiskeytown Lake.

A new addition to the Co-op Program is WxCoder. This system allows observers to enter and record their daily observations via the internet.

If you would like to obtain any of the data compiled by co-op observers, please contact the National Climatic Data Center in Asheville, NC at 704-271-4800, or the Western Region Climate Center in Reno, NV at 702-677-3140.

If you are a co-op observer and have questions, need supplies, or have an equipment problem, please write to our Cooperative Program Manager through our Webmaster e-mail address.