Record Setting Cold March in Alaska
This is an “early” post highlighting some aspects of the very cold March over most of Alaska. I’ll have more details early next week after the ERA5 reanalysis data for the month becomes available. One of the impacts of the sustained cold weather has been exceptionally high sea ice extent in the eastern Bering Sea, which I wrote about here.
Temperature Overview
March was historically cold over most of Alaska except for the North Slope and Bering Strait, and capped off what in many areas was remarkably cold 2025-26 winter season.
Temperatures averaged 10°F (5.6°F) or more below normal over a large portion of Alaska south of the Brooks Range except for Northwest Arctic Borough, the Seward Peninsula and the immediate Bering Sea coast. Because of the strong maritime influence, southeast Alaska and the Gulf coast were much colder than normal, but except in northern Southeast not to the 10°F level. The largest departures, in some places in excess of 20°F, were in the Tanana Valley and in the Lake and Peninsula Borough in southwest mainland Alaska.
There were only a few Marchs during the past 120 years that were even approximately this cold in Alaska, and interestingly, none of those super-cold March occurred prior to 1950. In the NOAA/NCEI analyses, at the statewide level, the five coldest Marchs since 1925 have all been since the 1960s (with the addition of this March, the five coldest will all be since 1970). The time series for March average temperatures since 1930 (Fig. 2) shows no trend. However, this is a rare example when there actually is a statistically significant trend toward higher year-to-year variability, helped out by the mildest March (2019) and coldest March (2026) occurring in the past decade.
March was the coldest on record at a number of long-term climate stations in Interior, Southcentral and southwest Alaska, including:
Fairbanks Airport: -9.0F (since 1930)
Delta Junction/Ft. Greely: -5.8F (since 1942)
Tok: -7.7F (since mid 1950s)
Northway: -11.5F (since 1943)
Eagle: -11.3F (since 1902 but with significant gaps)
Denali National Park HQ: -5.9F (since 1924)
Glennallen: -4.6F (since 1966)
Anchorage Airport: 13.4F (since 1953)
King Salmon +1.4F (since 1942)
Haines 22.6F (1926 but a large gap mid-1950s to early 1970s)
Several other sites had the second coldest March of record, including McGrath and Nenana, where 1959 was colder and Palmer at the Matanuska Experiment Farm, where 2007 was slightly colder. Reporting the third coldest March included Tanana (1959 and 2007 colder) and Juneau (1967 and 1974 colder).
Tanana Valley Spotlight
From the list of places that had the (near) coldest March on record, there is a concentration in the Tanana Valley (blue dots in Fig. 3)
A major contributor to the record cold in the valley were many days (and nights) of completely clear skies. This is not unusual in March, but persistent high pressure supported by north to northwest winds aloft, a cold airmass in place, light winds and a deep snowpack led to especially large day-to-night swings in temperatures. At Fairbanks Airport, the March average diurnal range of 34.7°F (19.3°C) is the second highest on record for any month (only March 2011 was larger). Again for Fairbanks Airport, the daily average high temperature in March 2026 was not as low as in 1959 or 2007, but the daily average low temperature was, by 6°F, the lowest on record. This is partially why cooperative sites in the Fairbanks area at slightly higher elevations did not have the coldest March of record: the strong morning temperature inversion were extremely shallow, so daily low temperatures were nowhere near as low. For example, at the College Observatory cooperative site, at the University of Alaska Fairbanks Troth Yeddha’ (West Ridge), the climate site is 4 miles north of the Airport weather station but 150 feet higher elevation, the March average low temperature was 10°F higher than the airport, with individual days as much as 20°F higher (Fig 3).
Another highlight of the month in the Tanana valley was a lack of any mild days at all, with most places staying below freezing all month. At Fairbanks, the high temperature of 30F (-1.1C) made this the first March since 1918 when the temperature failed to get above freezing at least one day in March. This helped keep area trails in good shape and not icy in spite of little new snow during the month. Other high temperatures for March included 29F (-1.7C) at Nenana and 31F (-0.6C) at Delta Junction and Tok and only 27F (-2.8C) at Northway.
GREAT Summary!
Excellent looking forward to the next winter write up