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The New Climate Normals

On May 4, 2021, the National Oceanic and Atmospheric Administration (NOAA) revealed new climate normals spanning the 1991 – 2020 timeframe. These 30-year averages are calculated from measurements of weather variables like temperature and precipitation from thousands of weather stations across the entire country. The data get corrected for erroneous or missing values and the process takes many months to ensure good data quality control. What do these new normals mean for the state of Alaska? Climate warming occurred all across the state, with the most significant warming along the North Slope, the Arctic Coast and the adjacent Arctic Ocean from the Beaufort to the Chukchi Sea. This is tied to the distinct changes in the extent of sea ice: there has been significantly less sea ice in recent years, with historic lows recorded in the Bering Sea. In Alaska, the normal temperature has risen nearly 1 degree Fahrenheit since the 1981 – 2010 period. Fall temperatures were notably warmer compared to 1981 – 2010 while summer temperatures are only slightly warmer in most places. Fairbanks is no longer considered a sub-Arctic climate, instead termed a “warm summer continental” climate due to May now having an average temperature above 50 degrees Fahrenheit.

Many areas of the state are seeing increasing precipitation, although the location is much more varied. In places where normal precipitation has not changed significantly, the seasonal normal is shifting with less snow in the fall and more during the winter – an overall shortening of the snow season. Anchorage, for example, is seeing more snow but it’s being concentrated into a shorter period of time: while snowfall totals for the season have gone up 3.5 inches, October’s snowfall totals have dropped by more than 2 inches. 

More information on the calculation methodology for the new normals can be found here.

Read more about this in our 2020 Annual Report, coming soon.

Temperature anomaly for the state of Alaska, showing the change in annual normal temperature (1991 – 2020 normal minus 1981 – 2010 normal), as derived from the ECMWF ERA5 4th generation reanalysis data (data source: Climate Reanalyzer, Climate Change Institute, University of Maine).

Precipitation anomaly for the state of Alaska, showing the change in annual normal temperature (1991 – 2020 normal minus 1981 – 2010 normal), as derived from the ECMWF ERA5 4th generation reanalysis data (data source: Climate Reanalyzer, Climate Change Institute, University of Maine).