The U.S. Climate Reference Network (CRN) is a network of climate stations now being developed as part of a National Oceanic and Atmospheric Administration (NOAA) initiative. The primary goal of its implementation is to provide future long-term homogeneous observations of temperature and precipitation that can be coupled to past long-term observations for the detection and attribution of present and future climate change. Data from the CRN will be used in operational climate monitoring activities and for placing current climate anomalies into an historical perspective. The CRN will also provide the USA with a reference network that meets the requirements of the Global Climate Observing System (GCOS). If fully implemented, the network will consist of about 250 stations nationwide.