United States Historical Climatology Network (USHCN), Version 1 (Superseded Version)

**This dataset has been superseded by a newer version. This version of the data should not be used except in rare cases (e.g., when reproducing studies that used this earlier version).** The U.S. Historical Climatology Network Monthly Data, Version 1 contains precipitation and temperature data adjustments to the monthly mean maximum, minimum, and average temperature data that addressed potential changes in biases (inhomogeneities) in data from USHCN stations documented in NCEI's station history archives. The USHCN is comprised of 1221 high-quality stations from the U.S. Cooperative Observing Network within the 48 contiguous United States. Stations have been selected according to coverage, length of data record and completeness, and historical stability. Data includes sets of Maximum, Minimum and Average Temperature and Precipitation data that are adjusted based on several qualifiers, including: time of observation (Karl et al. 1986), station moves and instrument changes (Karl and Williams, 1987; Quayle et al., 1991), and apparent urbanization effects with a specific urban bias correction (Karl et al. 1988). Included with the data set are metadata files that contain station history information about station moves, instrumentation, observing times, and elevation.

The archive also includes data that is not officially USHCN data but is from stations in the network: Daily Snow Depth (1893-1992) and Monthly Sunshine and Clouds (1891-1987).