Three new feature layers are available from the NOAAGlobalTemp dataset: the latest monthly temperature analysis, the full monthly archive from 1880 – present, and the annual average from 1880 – present. All of them compare the observed temperature to the 1971-2000 base period** (so -2oC means 2o cooler than the 1971-2000 average).
Learn more about them, and how they can be used, by reading a recent blog article by @DanPisut - Official global climate data now in ArcGIS Living Atlas.
