For the past 100 years, a mostly volunteer group of observers has formed the backbone of the U.S. National Weather Service (NWS) Cooperative (CO-OP) network. These stations have provided most of the observations used to satisfy the Department of Commerce's statutory mandate of 1890... "to establish and record the climatic conditions of the United States" (15 USCA 313). Originally, this network was intended primarily for agriculture, but many other uses of the data have since emerged, such as the climatic planning of weather sensitive activities, input to engineering design studies, and input and verification for weather and river forecasts. In recent years, heightened awareness regarding climatic change and variability has challenged this network with yet another mission: the monitoring and detection of climate change. While not designed for that mission, the CO-OP network has proved useful in this respect. However, with some changes in operation, it could become even more valuable in monitoring for climatic change, and could do so in a most economical way. Similar practices instituted worldwide will be necessary for comprehensive study of climate change to the degrees of detail necessary to address specific policy issues and practical local-scale decision making.