The Köppen code for Reykjavík, Iceland, is Cfc, a subpolar oceanic climate. The code identifies a cool maritime environment rather than an Arctic tundra climate.
Reykjavík’s coastal position gives it relatively mild winters for a city at 64° north. The North Atlantic Current, an extension of the Gulf Stream, moderates temperatures, while the surrounding ocean helps keep summers cool. Winter gales are common under the influence of the Icelandic Low.
The final letter, “c,” means that fewer than four months average above 10 °C. Reykjavík’s summer temperatures commonly range from 10 to 15 °C and rarely exceed 20 °C. Its winters can still be cold, but temperatures very rarely fall below −15 °C.
A common mix-up is ET, the tundra classification, because Reykjavík lies near the Arctic Circle. However, its mild maritime temperatures prevent it from meeting the tundra threshold. Reykjavík’s extreme seasonal daylight—near-continuous daylight in June and fewer than five daylight hours in parts of December—is a separate astronomical feature, not a Köppen code.