Climate and monthly weather forecast
Keflavík International Airport, Iceland

Situated on the southwestern tip of Iceland, Keflavík International Airport’s environment is predominantly subject to Cfc or Marine West Coast climate, with cool summer, as per the Köppen climate classification. Bearing the characteristics of this particular classification, the location experiences a steady pattern of weather throughout the year. Changes are subtle, yet profound in influencing the overall climatic dynamics.

A subtle fluctuation in the parameters from month to month cements the weather pattern. Sea temperature exhibits a range from 4.8°C (40.6°F) to 11.4°C (52.5°F) across the yearly spectrum. On this basis, the ocean is relatively colder during January to March, with the coldest being March at 4.8°C (40.6°F). It warms up from April onwards, reaching its peak in July at 11.4°C (52.5°F), only to cool down gradually in the subsequent months. Interestingly, the sea temperature returns to its starting point by the end of the year, closing the year-long cycle.

The trend of daylight hours offers a more dramatic curve. Beginning at 5.6 hours in January, daylight sees a steady increase, taking a massive leap between February and April, where it jumps from 8.6 hours to 15.1 hours. The longest days are witnessed around June, offering light for an extended 20.8 hours. However, post-summer, there is a rapid decrease, taking daylight hours back to a mere 4.5 hours in December.

There are no distinct months without rainfall or exceedingly hot or cold. This location, being on the cooler side, does not possess extreme temperature variants.

Determining the best time to visit largely depends on the visitors' preferences. If longer days and milder sea temperatures are the preference, then June and July, with 20.8 hours and 19.5 hours of daylight respectively, alongside a relatively warmer sea temperature of 11.4°C (52.5°F) to 11.3°C (52.3°F) would be ideal. It is important to remember that "warm" is subjective, and in this scenario, it indicates less cold than the majority of the year.

Visiting during March or December might pose some challenges. March witnesses the coldest sea temperature of 4.8°C (40.6°F), and December brings the shortest daylight of 4.5 hours, not leaving much time for outdoor activities. However, suppose winter activities are on the agenda. In that case, these months might present the right environment alongside necessary caution with the light restrictions.

Spring slowly starts to warm up the environment after the winter chill at Keflavík International Airport. Sea temperatures range from 4.8°C (40.6°F) to 7.2°C (45°F). Daylight hours show a significant increase across these months - from 11.8 hours in March, 15.1 hours in April to 18.4 hours in May. Activities may be comfortably planned given the generous daylight, acknowledging that the temperatures can still be slightly chilly.

Summer in Keflavík boasts the warmest sea temperatures and the longest days. June brings sea temperatures averaging 9.3°C (48.7°F), and July elevates it to the annual peak of 11.4°C (52.5°F). The day begins to stretch from June’s 20.8 hours, slightly dropping to 19.5 hours in July. Along with this, daylight even persists above 16 hours until August. Activities are abundant as the warmest and longest days are present.

Autumn sees a significant dip in both daylight and sea temperatures. The sea temperature starts at 9.8°C (49.6°F) in September, gently falling to 7.2°C (45°F) by November. Daylight hours retract significantly from 13 hours in September, 9.7 hours in October, dropping to 6.6 hours by November. Activities need careful planning during this time, considering the significant reduction in daylight.

Winter in Keflavík introduces the shortest days and cold sea temperatures. The sea temperature linger between 6.6°C (43.9°F) in December and 5.3°C (41.5°F) in February. Meanwhile, daylight hours dwindle from 4.5 hours in December to 5.6 hours in February. Outdoor activities must be timed cautiously during this period, acknowledging the limited availability of daylight.

January sports the coldest sea temperatures of the year in Keflavík International Airport, plunging to an icy average monthly low of 5.3°C (41.5°F). These conditions significantly influence the proximate air temperatures making this time of the year quite frosty. Weather in January »

The transition from January to February in Keflavík International Airport hardly brings any temperature difference, maintaining the sea temperatures at 5.3°C (41.5°F). Albeit, a significant change is the extended daylight hours heralding a welcome change. Weather in February »

As March rolls in, a slight dip in the sea temperature is noted at Keflavík International Airport, recording 4.8°C (40.6°F). This decrease is coupled with considerable progress in the lengthening daytime which results in moderate thermal conditions. Weather in March »

April sparks a notable upswing at Keflavík International Airport, with the sea temperatures climbing to a more bearable 5.8°C (42.4°F). This time of the year signals a clear transition from the cold months as April showers begin to wash away the winter blues. Weather in April »

Come May, Keflavík International Airport experiences a sea-temperature surge to 7.2°C (45°F), signaling an evident transition into warmer seasons. Accompanying this increase is an explosion in daylight hours, painting the surroundings with longer-lasting sunlight that lingers into the evening. Weather in May »

June displays a remarkable upsurge at Keflavík International Airport, reaching a sea temperature high of 9.3°C (48.7°F) for the year so far. It is a time of great migration as a variety of bird species flocks the area, enriching the biodiversity of the region. Weather in June »

The sea temperatures tally to another high in July at Keflavík International Airport, climbing to a peak of 11.4°C (52.5°F). The weather is mild, with the sun generously granting the longest daytime hours. The conditions favor a plethora of outdoor activities, from bird-watching to hiking along the scenic routes. Weather in July »

August sees a minimal dip in the sea temperatures at Keflavík International Airport, settling at an average of 11.3°C (52.3°F). The weather remains generally acceptable for outdoor activities, but a notable reduction in daylight hours signals a gradual transition from summer to autumn. Weather in August »

Pacing towards the end of the third quarter of the year, Keflavík International Airport experiences a fall in sea temperature, with a decrease to 9.8°C (49.6°F) in September. This drop is a sign of the approaching colder months, and the distinct crispness in the air becomes apparent. Weather in September »

October in Keflavík International Airport features a mild decline in sea temperatures, settling at an average of 8.3°C (46.9°F). This period is characterized by colder months lingering on the horizon and daylight hours swiftly shrinking. Weather in October »

The shift into November sees a further plunge in sea temperatures at Keflavík International Airport, recording a descent to 7.2°C (45°F). This period increasingly leans towards winter, with a sharp fall in daylight hours and the onset of freezing conditions. Weather in November »

In December, Keflavík International Airport registers a cold average monthly sea temperature of 6.6°C (43.9°F), marking the advent of the coldest season. Daylight hours dwindle quite significantly, often resulting in a fair share of gloomy days. Weather in December »