United States Historical Climatology Network (USHCN), Version 2.5

The U.S. Historical Climatology Network Monthly Data, Version 2.5 consists of precipitation and temperature data "corrected" for changes in station location, instrumentation, and observing practices. The vast majority of stations are from the NOAA Cooperative Observer Program (COOP) Network. 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 either (1) raw (non-adjusted though flagged for possible quality issues), (2) adjusted due to time of observation bias (TOB) or (3) put through the Pairwise Homogenization Algorithm (PHA). The data also is archived with station information and source code for reading the data.