Easterling, D. R., T. R. Karl, E. H. Mason, P. Y. Hughes, and D. P. Bowman National Oceanic and Atmospheric Administration National Climatic Data Center Asheville, North CarolinaThis document describes a database containing monthly temperature and precipitation data for 1221 stations in the contiguous United States. This network of stations, known as the United States Historical Climatology Network (U.S. HCN), and the resulting database were compiled by the National Climatic Data Center, Asheville, North Carolina. These data represent the best available data from the United States for analyzing long-term climate trends on a regional scale. The data for most stations extend through December 31, 1994, and a majority of the station records are serially complete for at least 80 years. Unlike many data sets that have been used in past climate studies, these data have been adjusted to remove biases introduced by station moves, instrument changes, time-of-observation differences, and urbanization effects.
These monthly data are available free of charge as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center. This NDP includes documentation and 27 machine readable data files consisting of supporting data files, a descriptive file, and computer access codes. The entire database takes 355 MB of disk space, with the largest file being 16 MB. The published documentation for this NDP describes how the stations in the U.S. HCN were selected and how the data were processed, defines limitations and restrictions of the data, describes the format and contents of the magnetic media, and provides reprints of literature that discuss the editing and adjustment techniques used in the U.S. HCN.