The Iceland December heat record was broken on Christmas Eve in Seyðisfjörður, eastern Iceland, where a weather station recorded 19.8°C, according to Icelandic broadcaster RÚV.
A spring-like Christmas in the Eastfjords
Seyðisfjörður is a small fjord town in East Iceland, usually associated with snow, winter storms and sub-zero nights in December. This year, however, residents saw rain and bare ground instead of a white Christmas as temperatures briefly climbed close to 20°C.
RÚV reported that the reading was recorded around 23:00 on Christmas Eve, and that the same warm air mass also pushed temperatures to 19.7°C in Bakkagerði (Borgarfjörður eystri) earlier in the event. Meteorologists stressed that instruments and data are routinely reviewed after extreme values, but that there was no immediate reason to doubt the measurements.
Why Seyðisfjörður reached 19.8°C in late December
The Icelandic Meteorological Office (Veðurstofa Íslands) linked the conditions to a combination of very mild air over the island and strong winds.
When warm air flows across mountainous terrain, Iceland can experience a local foehn effect known as hnúkaþeyr: clouds form over the mountains, and air warms further as it descends toward the coast. In practical terms, that can turn a moist, windy winter day into a surprisingly warm spell in specific valleys and fjords—especially in North and East Iceland.
How unusual is 20°C in Icelandic winter
Even in Iceland, warm spikes do happen during winter storms, but the timing and intensity remain exceptional. The previous national December maximum was 19.7°C, set on 2 December 2019 at Kvísker in Southeast Iceland.
A one-off record does not, on its own, prove a climate trend. Still, it is consistent with a North Atlantic region where extremes—both mild and harsh—are becoming more relevant for public safety, infrastructure and emergency planning.
Climate context: Arctic amplification and Iceland’s warming trend
Iceland sits at the meeting point of Arctic and Atlantic air masses, which makes it particularly sensitive to shifts in circulation patterns. Climate monitoring by the Icelandic Meteorological Office shows a clear warming trend since 1980, with average temperatures rising faster than the global mean.
Scientists describe the broader high-latitude pattern as Arctic amplification—a phenomenon where the Northern Hemisphere’s high latitudes warm more rapidly than the planet as a whole. For Nordic and North Atlantic countries, this adds pressure on adaptation planning, from avalanche and landslide risk to winter road safety and coastal infrastructure.
What happens next: a sharp cooldown is still possible
Forecasters in Iceland have warned that these warm episodes can be short-lived. As wind direction changes and colder air returns, temperatures can fall quickly—sometimes within hours—bringing sleet, snow and icy roads back into the same regions that just saw record warmth.
For now, the December record in Seyðisfjörður is another reminder that weather variability in the North Atlantic is not just a summer story—and that winter extremes are increasingly part of the conversation for Iceland and the wider Nordic region.
