The Icelandic climate 

"If you don’t like the weather right now, just wait five minutes," people sometimes say in Iceland. This is an indication of the strong variability of the Icelandic climate, where one may occasionally experience the four seasons over a day: sunshine and mild temperatures; windy, cool temperatures and rain; snow and temperatures below zero degrees C. 
When this happens (rarely), it is an expression of the location of Iceland at the border between Arctic and temperate seas, and between cold air masses of the Arctic and warm air masses of lower latitudes.

Ocean currents and sea temperatures - Iceland, located at 63-67°N and 18-23°W, has considerably milder climate than its location just south of the Arctic Circle would imply. A branch of the Gulf Stream, the Irminger Current, flows along the southern and the western coast greatly moderating the climate.

The cold East Greenland Current flows west of Iceland, but a branch of that current, the East Icelandic Current, approaches Iceland’s northeast- and east coasts. This is reflected in the coastal sea surface temperatures around Iceland. They are generally close to +2°C during the coldest months (January-March).

Sea temperatures rise to over +10°C at the south- and west coasts of Iceland during the summer, slightly over +8°C at the north coast, but are coolest at the east coast where summer sea temperatures remain below +8°C. During years with heavy sea ice off northern Iceland, sea temperatures during summer can remain close to winter temperatures.