Looking at the temperatures in Barrow since the beginning of October, it is evident that warm temperatures have been the rule. In fact, 77% of the days between October 1st and February 12th have been above normal.
The first chart shows the average daily temperature departure from normal (1981-2010) during that time period. Since October 1st, the average day has been 7.5°F above normal.
The second chart shows the same information as the first but instead of daily temperature departure measured in degrees Fahrenheit, it shows the daily departure in standard deviations. The median daily departure from normal as measured in standard deviations was 0.67 based on the 1981-2010 climate normal period. According to a standard z-score table, 25% of days should be more than 0.67 standard deviations above the mean – not 50%.
Finally, the last chart shows the average temperature between October 1st and February 11th for each winter since '20-'21 until the present. The current winter is far and away the warmest during those 90+ years – by 2.1°F! There is data that goes back before 1920 at Barrow but it has significant data quality issues. Still, this year is warmer than any complete year prior to 1920 as well. Certainly the lateness of the sea ice in recent decades has significantly contributed to early season warming in particular.
The two maps below are from the ESRL Reanalysis data sets. The first map shows the temperature anomalies for Alaska during the months of October through December for the last 10 years. The second map shows the temperature anomalies for Alaska during the months of February through April for the last 10 years. The lack of sea ice in the Fall and early winter dramatically warms the northern portions of Alaska. Once the winter ice pack has set in, the temperature anomalies are greatly reduced. On the second map you can see the cold anomaly in the southeast Bering Sea due to high spring ice extents and cold water temperatures.