Climate and monthly weather forecast
Siglufjörður, Iceland

Siglufjörður, located in the island-nation of Iceland, is dominated by an austere Tundra climate, as per the Köppen climate classification's ET criteria. This classification suggests a frigid temperature year-round with scanty rainfall. The little warmth that the sun provides, pairs persistently with the chill of the oceanic environment of this coastal town.

Throughout the year, the town experiences noticeable variations in daylight hours and sea temperature. Daylight drastically swings from a mere 3 hours in December to a substantial 23.6 hours in June. This shift in daylight illumination reflects Iceland's location near the Arctic Circle and its concomitant experience of the midnight sun phenomenon.

Sea temperature in Siglufjörður gradually fluctuates around the year, starting at 3.3°C (37.9°F) in January and dipping to its lowest in February at 1.9°C (35.4°F). From then, a steady incline transpires peaking in August at 9.2°C (48.6°F) before tumbling down again towards the year-end. These sea temperatures further contribute to the town's chilly and damp surroundings, occasionally giving rise to fogs and mists, especially during colder months. Observing these variations aids in comprehending the unique climate dynamics of Siglufjörður, a key to preparing for its harsh weather conditions.

The optimal period to escape to Siglufjörður comes with long daylight hours, from the crisp end of spring, through the breezy summer months, extending into the early autumn. Specifically, between May and August, daylight hours soar from 19.4 to 23.6 hours—an ideal period for sightseeing and indulging in explorative activities under the radiant midnight sun. The sea, relatively warmed up during these months, ranging from 5.9°C (42.6°F) to 9.2°C (48.6°F), slightly tempers the otherwise nippy aura of the town.

The chill and darkness of the intense Icelandic winter mark the most challenging period to visit Siglufjörður, extending from late autumn to winter's end, between October and January. During these months, the daylight diminishes sharply from 13.1 to 3 hours. The brief hours of illumination, coupled with plunging sea temperatures, which drop from 7.2°C (45°F) in October to 3.3°C (37.9°F) in January, contribute to a very cold environment—the sort that offers a tough test of resilience for visitors not familiar with such extremities.

Midway between winter and summer, springtime in Siglufjörður comes with rapidly lengthening daylight hours—progressing from 11.8 hours in March, soaring to 19.4 hours in May. The increasingly warm sea, escalating from 2.1°C (35.8°F) to 5.9°C (42.6°F), blends with extended sunlight to form a more tolerable environment. The milder, yet still cold, spring weather motivates life in both fauna and flora, strumming an invigorating tune of revival across the tundra landscape.

Summer ushers in a broad daylight span, peaking at 23.6 hours in June before gradually descending to 16.8 hours in August. Bathed in near constant sunlight, the town embraces nature's generosity, showing off the beauty of the tundra in its warmest guise. Notably warmer sea temperatures, oscillating from 5.9°C (42.6°F) to 9.2°C (48.6°F), wisp away some of the chill, shaping the most affable period for outdoor activities and exploration in this northern town.

Autumn in Siglufjörður is marked by swiftly shortening daylight from 13.1 hours in September to just 5.8 hours by November. Throughout these months, the sea temperature considerably cools, dropping from 7.2°C (45°F) to 4.8°C (40.6°F). The combination of the dwindling daylight and the crisp temperatures pave the way for the onset of the hard Icelandic winter and the transition provides a spectacle of changing colours.

Winter cloaks Siglufjörður in short daylight hours and plunging temperatures with December marking the darkest point of the year at a mere 3 hours of daylight. Sea temperatures register their lowest during winter, managing a slight rise from 4.4°C (39.9°F) in December to a still frigid 3.3°C (37.9°F) by January. Pervading this season, snowfall transforms the town into a picturesque winter wonderland—albeit a harsh one. Winter in Siglufjörður, while difficult to endure, unveils a raw, icy charm that is truly unique to the Arctic tundra.

January experiences the chill of winter as the weather dips, making it the coldest month in Siglufjörður, Iceland. With a sea temperature at 3.3°C (37.9°F), cold winds from the North Atlantic significantly impact the overall weather condition. Weather in January »

As one progresses from the icy grip of January, February presents a slight uptick in daylight hours to 8.2. The sea temperature hits a low of 1.9°C (35.4°F) which, together with chilly gusts of wind, contributes to an overall cool climate. Weather in February »

March indicates the transition from winter to spring, as weather conditions slowly start to improve from the depths of the severe February cold. Although the sea temperature remains quite low at 2.1°C (35.8°F), daylight steadily increases to 11.8 hours providing a brighter environment. Weather in March »

The subtle warmth of spring begins to pervade the atmosphere in April. Daylight hours extend considerably to 15.5 hours, and the sea temperature experiences a moderate increase to 2.9°C (37.2°F). The radiant sunshine starts to dominate the sky, delivering a stark contrast to the prevailing gloom of the previous month, March. Weather in April »

In May, the temperature of the sea climbs to a decent 3.9°C (39°F) heralding the onset of warmer conditions. There is a substantial increase in daylight hours to 19.4 hours, marking this month as a time of elongated days. As one steps into May from April, the weather becomes relatively clear making it an ideal time for outdoor activities. Weather in May »

June ushers in the summer season in Siglufjörður with an appreciable rise in the sea temperature to 5.9°C (42.6°F). Daylight reaches its peak for the year at 23.6 hours, allowing residents to fully enjoy the much-anticipated Midnight Sun. Weather in June »

July has a pleasantly warm sea temperature of 8.4°C (47.1°F), providing a welcome contrast to the freezing waters of the prior months. Daylight hours slightly decrease from June's peak to 21.1 hours, but this subtle dip is scarcely noticeable as the Summer Solstice ensures ample light throughout the day. Weather in July »

The weather in August starts to cool down gradually as the peak summer months wind down. Daylight hours recede a little further to 16.8 hours, and the temperature of the sea reaches its highest at 9.2°C (48.6°F). From July to August, there is a minor escalation in sea temperature, granting everyone the chance to partake in water-based activities. Weather in August »

September marks the onset of autumn in Siglufjörður, as the sea temperature begins to dip to 7.2°C (45°F). The daylight hours continue on a downward trajectory, settling at around 13.1 hours. Compared to the warmer period of August, September brings a perceptible change in the climate, with a gradual cooling trend. Weather in September »

Siglufjörður's weather in October plunges further into autumn as daylight hours shrink to 9.5 hours and the sea temperature drops to 5.4°C (41.7°F). Unlike September, October heralds the early signs of winter, with crisp air and shorter days becoming more prominent. Weather in October »

As the year nears its end, November witnesses a further drop in the sea's temperature to 4.8°C (40.6°F) and daylight hours dwindling down to 5.8 hours. The weather in Siglufjörður begins to reflect the chilly aura of the approaching winter more tangibly than the previous month of October. Weather in November »

December welcomes the heart of winter in Siglufjörður with daylight hours decreasing to their yearly low at 3 hours. Sea temperature is about 4.4°C (39.9°F), contributing to the overall cold atmospheric conditions distinctive of this month. Weather in December »