Historical growing degree days (GDD), a measure of heat accumulation in plants which indicates cumulative seasonal warming above a base temperature of 50°F. Geographic units: HUC10.
These data are part of a set that includes historical (1970-1999) values plus two projections each for two future time periods, 2050s (2040-2069) and 2080s (2070-2099), based on lower and higher greenhouse gas emission scenarios, RCP 4.5 and RCP 8.5.
When rendered and displayed in Map Viewer (web map): Data classes and symbology by Robert Norheim, Climate Impacts Group, based on the CMIP5 projections used in the IPCC 2013 report.
Data source: Mote et al. 2015.