Autumn 2025 Arctic Climate Summary
Near record warmth…again
Autumn 2025 was another very mild season for the Arctic as a whole. For lands and seas north of 60°N, the September through November average temperature of -4.45°C was 1.90°C above the 1991-2020 baseline based on ERA5 analysis. A whooping 82 percent of the Arctic had average temperatures this autumn that were above the 1991-2020 baseline (98.5 percent of the Arctic was above than the 1951-80 baseline average). Additionally, 34 percent of the Arctic had ”top three” warmest autumn since 1950.
North America was especially mild. In the Canadian North, Nunavut, Northwest Territories and the Yukon Territory each had the warmest autumn on record in ERA5 reanalyses since 1950. To the east and west of Canada, Greenland had the third mildest autumn and Alaska sixth. In contrast, most of the Asian Arctic had autumn temperatures average near to a bit below the modern normal.
2025 was the third highest autumn average temperature on record for the Arctic, based on ERA5 since 1950, very slightly below last year (Fig 2). Autumn 2020 remains the mildest. Since the early 1990s, the Arctic average autumn temperature has increased by about 3.6°C. To put this in perspective, the September-November global average temperature since 1990 has increased by 1.0°C.
Sea surface temperatures
Sea surface temperatures for the autumn overall were far above normal on the Atlantic side of the North Pole. This was most dramatic in the Barents and Kara Seas, but also in Baffin Bay and Hudson Bay, due in part to the lack of sea ice. The largest area of below normal SSTs were on the Pacific side of the Pole, in a band between about 70°N and 73°N from the the East Siberia Sea eastward through the Beaufort Sea. Near the ice pack edge, (actual or climatological), sea surface temperature departures can be both a cause and effect of atypical sea ice conditions.
Precipitation
Precipitation always has much higher spatial variably relative to normal compared to temperatures. Overall, Arctic-wide autumn precipitation (rain plus the water equivalent of snow) was 3 percent above the 1991-2020 average but this was still the lowest since 2016.
Significantly above normal autumn totals occurred this autumn from central Alaska northeast into the Canadian Arctic Islands as well as the Nordic Arctic and Svalbard (Fig. 4). Totals were significantly below normal in eastern Greenland, Iceland and much but not all of the Asian Arctic.
Snow and ice extent
The seasonal snow pack was established across Arctic lands during autumn (Fig. 5). Arctic snow cover at the start of September was confined to high elevations and much of the Canadian Arctic Archipelago. Snow cover expanded quickly in late September and early October across the Asian Arctic but was slow to take hold in the mainland Canadian Arctic. By the end of November, snow covered about 98 percent of Arctic lands, which is typical.
