We have used the GHCNm Version 4 dataset available here: ncei.noaa.gov/data/global-historical-climatology-network-monthly/v4/temperature/archive/. The data source flags are defined here ncei.noaa.gov/data/ghcnm/v4/temperature/doc/ghcnm-flags.
Repository: github.com/alexdum/ghcnm Report issue(s) or feature(s) request here