University of Alaska Fairbanks    |    Scenarios Network for Alaska + Arctic Planning

Freezing Index

The freezing index, or degree days below freezing, can be used to estimate the depth of ground freezing during the winter, the depth of ice that will be formed on a lake, or the amount of heat which must be added to an exposed water tank to keep it unfrozen.

Choose a location below by community name, coordinates, or by clicking on the map to select a point.

  • ✓  Modeled Historical (1980–2009, ERA Interim)
  • Projected Mid–Century (2040–2069, NCAR CCSM4, RCP 8.5)

Freezing index

These layers show the historical or projected freezing index across Alaska.

Degree days below 32°F
≥ 7000

The freezing index is the annual cumulative degree days (°F) below freezing for each location. These degree days are calculated by taking the number of degrees below 32°F for each day of the year and adding them together into a single value. A higher freezing index means a colder year for that location.

Larger values indicate colder winter temperatures. A decrease in freezing index over time suggests warming conditions and decreased depth and duration of freeze in soils and water bodies.