This dataset consists of four different variables: degree days below 65°F (or "heating degree days"), degree days below 0°F, degree days below 32°F (or "air freezing index"), and degree days above 32°F (or "air thawing index"). All were derived from the same set of nine statistically downscaled CMIP5 global climate model outputs driven by RCP 4.5 and RCP 8.5 emissions scenarios. A historical baseline (Daymet, 1980-2017) dataset is included for each variable. All data are in GeoTIFF format and have a spatial resolution of 12 km.

Units are degree days Fahrenheit (°F⋅days).

The model-scenario combinations are:

- ACCESS1-3, RCP 4.5

- ACCESS1-3, RCP 8.5

- CanESM2, RCP 4.5

- CanESM2, RCP 8.5

- CCSM4, RCP 4.5

- CCSM4, RCP 8.5

- CSIRO-Mk3-6-0, RCP 4.5

- CSIRO-Mk3-6-0, RCP 8.5

- GFDL-ESM2M, RCP 4.5

- GFDL-ESM2M, RCP 8.5

- inmcm4, RCP 4.5

- inmcm4, RCP 8.5

- MIROC5, RCP 4.5

- MIROC5, RCP 8.5

- MPI-ESM-MR, RCP 4.5

- MPI-ESM-MR, RCP 8.5

- MRI-CGCM3, RCP 4.5

- MRI-CGCM3, RCP 8.5

The .zip files that are available for download are organized by variable. One .zip file has all the models and scenarios and years for that variable. Each GeoTIFF file has a naming convention like this:

"ncar_12km_{model}_{scenario}_{variable}_{year}_Fdays.tif"

Each GeoTIFF has a 12 km by 12 km pixel size, and is projected to EPSG:3338 (Alaska Albers).