Global Historical Climatology Network - Monthly (GHCN-M), Version 2

**Please note, the temperature portion of this dataset has been superseded by a newer version. Users should not use this version except in rare cases (e.g., when reproducing previous studies that used this version). The precipitation subset of this dataset is still the latest version available.** The Global Historical Climatology Network Monthly (GHCN-M) Version 2 dataset created by the NCDC contains historical temperature, precipitation, and pressure data for thousands of land stations worldwide. The period of record varies from station to station, with several thousand extending back to 1950 and several hundred being updated monthly. Both historical and near-real-time GHCN-M data undergo rigorous quality assurance reviews. These reviews include pre-processing checks on source data, time series checks that identify spurious changes in the mean and variance, spatial comparisons that verify the accuracy of the climatological mean and the seasonal cycle, and neighbor checks that identify outliers from both a temporal and a spatial perspective. Only one file for the temperature data is available from the archive (file is for period of record ending in 2011), but precipitation data has been archived daily since 2012.