GHCN_CAMS Gridded 2m Temperature (Land)
GHCN CAMS is a high resolution (0.5x0.5) analyzed global land surface temperatures from 1948 to near present.
See the NCEI's GHCN_CAMS ftp page. According to the journal article on the dataset: A global monthly land surface temperature analysis for 1948-present. "This data set is different from some existing surface air temperature data sets in: (1) using a combination of two large individual data sets of station observations collected from the Global Historical Climatology Network version 2 and the Climate Anomaly Monitoring System (GHCN + CAMS), so it can be regularly updated in near real time with plenty of stations and (2) some unique interpolation methods, such as the anomaly interpolation approach with spatially-temporally varying temperature lapse rates derived from the observation-based Reanalysis for topographic adjustment.". Also see the webpage http://www.cpc.ncep.noaa.gov/cgi-bin/gl_Temperature-Monthly.sh for plots (total, monthly, percentile) and links to related datasets.