The extraordinary warmth across the Arctic basin in October prompted me to take a closer look at historical temperature data to get a sense for the magnitude of the recent anomalies. I first did a search for stations with reasonably complete monthly data since 1971, and then I selected 19 sites that lie on or near the coast and also fall within 2000km of the Arctic Ocean's pole of inaccessibility (marked with an X below). The spatial distribution of the 19 sites is reasonably even around the Arctic Ocean.
The chart below shows the mean temperature anomaly for these 19 stations in each October since 1971. Remarkably, the 19-station mean temperature in October 2016 was 5.6°C above the 1981-2010 normal and more than 2°C above the 2012 record. October 2016 was the second most anomalous calendar month in the data since 1971 - only January 2016 was warmer relative to normal, at +6.5°C.
Looking at recent daily temperature anomalies for the same 19 stations, it is amazing to see that the warmth has become even more pronounced since the end of October; the 19-station mean anomaly reached +9.6°C last Thursday (November 3), and on Friday the coolest of the stations was 5.4°C warmer than normal. In terms of standard deviations, Thursday's mean anomaly was the
highest of any day from 1971-present.
Here's the 19-station daily mean temperature for 2016 on an absolute scale rather than an anomaly scale. Only 7 out of 311 days have been cooler than the 1981-2010 normal, and then only by a fraction of a degree.
