May Weather in Keflavik, Iceland

Last updated: March 17, 2025

May in Keflavik, Iceland offers a vibrant spring atmosphere marked by a maximum temperature of 12°C (54°F) and an average of 7°C (44°F). Despite the mild conditions, temperatures can dip to a minimum of 0°C (33°F), reminding visitors of Iceland’s unpredictable climate. Rainfall is a common occurrence, with 115 mm (4.5 in) accumulated over 16 days, leading to a high humidity level of 85% that enhances the lush scenery. As nature awakens, this month is perfect for exploring the stunning landscapes shaped by both sun and showers.

May Temperature in Keflavik

As spring progresses into May, Keflavik, Iceland experiences a notable warming trend. The temperatures during this month range from a chilly 0°C (33°F) overnight to a comfortable 12°C (54°F) at the peak of the day, marking a significant shift from the lingering cold of earlier months. With an average temperature of 7°C (44°F), May brings a refreshing breath of warmer weather that is eagerly anticipated after the frigid winter months. This gradual rise in temperatures not only encourages outdoor activities but also signals the approach of the summer months, where the days become longer and sunnier.

May Weather in Keflavik: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in Keflavik, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec353636404448525248433836
Data source: Temperature data for Keflavik generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in Keflavik

In May, Keflavik experiences a precipitation level of 115 mm (4.5 in) over 16 days, signaling a gradual shift in weather as spring gives way to summer. This month's rainfall is slightly lower than the preceding April, which recorded 133 mm (5.2 in), but it's part of a consistent trend of relatively high precipitation in the earlier spring months, ranging from 110 mm to 126 mm from January to April. As the season progresses, rainfall tends to decrease, with June experiencing just 87 mm (3.4 in). Despite the reduction in precipitation, May's conditions still underscore the region's unpredictability, as the skies can shift rapidly, blending sunny days with sudden showers—a characteristic charm of Icelandic weather.

May Precipitation Trends in Keflavik

The chart displays monthly precipitation patterns in Keflavik, with values for each month alongside May's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec117126110133115877889171119119119
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

May Humidity in Keflavik

In May, humidity in Keflavik, Iceland, reaches a notable peak at 85%, marking the start of the summer season with a moist embrace. This increase follows a relatively consistent pattern through the spring months, where humidity hovers around 80%. As the year progresses into summer, humidity continues its upward trend, ultimately peaking in July and August at 87% and 88%, respectively. The data reveals a clear transition from late spring's cool dampness to the more pronounced humidity of summer, inviting visitors to enjoy the lush landscapes and vibrant natural beauty that flourish in these moist conditions.

May Average Humidity in Keflavik

This chart illustrates the average monthly humidity levels in Keflavik, with May's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how May's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec80%77%82%80%85%85%87%88%85%85%81%80%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Keflavik

As May arrives in Keflavik, Iceland, the UV Index climbs to a moderate level of 5, indicating an increase in sun intensity and the need for sun protection during outdoor activities. This marks a noticeable shift from the earlier spring months, where the UV Index remained relatively low with values of 1 to 3. As we transition from the cool confines of winter to the warmth of summer, the burn time decreases to just 30 minutes, emphasizing the importance of taking caution under the sun. With the UV Index peaking at 6 in June and July, continued awareness is essential for safe sun exposure. For detailed insights and a monthly breakdown, visit Keflavik UV Index.

Maximum UV Index Levels in Keflavik for May

The chart shows the monthly maximum UV Index (UVI) for Keflavik in May, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec112356643211
Data source: Keflavik May UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

May Sunshine in Keflavik

In Keflavik, Iceland, the transition into spring brings a remarkable surge in sunshine hours, with May standing out at an impressive 344 hours of glorious daylight. This notable increase follows a gradual climb from 42 hours in January, showcasing the gradual awakening of the region from its winter slumber. As days lengthen, May's sunlight contributes not just to a vibrant landscape but also to the invigorating spirit of the community, as outdoor activities flourish. This trend is mirrored in June and July, where sunshine remains abundant, but the peak in May marks a climactic moment in the seasonal shift. By August, the hours begin to taper off, yet the lingering warmth of May continues to resonate, making it a cherished month for both locals and visitors alike.

Monthly Sunshine Duration in Keflavik: May Highlighted

The May sunshine duration represents the total number of hours Keflavik experiences direct sunlight during the month of May, excluding cloudy or obstructed periods. This chart compares the sunshine duration of May with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec42h90h195h214h344h338h312h294h207h146h79h28h
Data source: Keflavik May Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Keflavik During May

As spring transitions into summer, May in Keflavik, Iceland, marks a notable increase in sunny weather, with a promising 49% chance of sunshine. This is a significant leap from the colder months, where the likelihood of clear skies hovers around 15-29%. Following the relatively gloomy April, May brings a refreshing change, as residents and visitors alike can enjoy more daylight and warmer temperatures. However, this sunny trend does not last into the summer months, as June experiences a dip back down to 18%, followed by even lower chances in July and August. Overall, May serves as a bright beacon of hope for daylight seekers, setting the stage for the summer season ahead.

Percentage of Sunny Days in May in Keflavik

The chart illustrates the percentage of sunny days in Keflavik throughout the year, with May highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Keflavik experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec29%18%15%26%49%18%13%12%15%26%22%20%
Data source: Keflavik May chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Keflavik in May

May in Keflavik, Iceland, ushers in a vibrant transition to longer days, with 18 hours of daylight illuminating the landscape. This month stands as a striking contrast to the shorter, darker winter months, where January offers just 5 hours of light. As the year progresses, daylight increases dramatically from 8 hours in February to a significant 15 hours by April, showcasing a clear upward trend toward the peaks of summer, which boasts nearly 20 hours of daylight in June. This gradual increase not only invigorates outdoor activities but also enhances the breathtaking beauty of Iceland's dramatic scenery, making May a truly enchanting time to explore and experience the northern charm of this unique region.

Average Daylight Hours in Keflavik for May

The chart illustrates the variation in daylight duration in Keflavik throughout the year, with May highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec5h 34m8h 35m11h 50m15h 8m18h 26m20h 42m19h 24m16h 11m12h 55m9h 40m6h 28m4h 24m
Data source: Keflavik daylight hours, calculated by summing the hours between sunrise and sunset for each day.

May Winds in Keflavik

May in Keflavik, Iceland, brings a refreshing shift in wind patterns, with the average wind speed dropping to 5.0 m/s (11 mph)—the calmest month of the year. After a steady decline from the higher winds of January through April, May offers a moment of respite, setting the stage for the mild summer months ahead. Interestingly, as the winds settle, this tranquil period transitions into a gradual increase again in June, reaching 5.8 m/s (13 mph). This seasonal ebb and flow highlights May's unique role as a bridge between the brisk spring winds and the more varied summer breezes, inviting both tranquility and a sense of change in the breathtaking Icelandic landscape.

Average May Wind Speed in Keflavik

The chart displays monthly wind speed patterns in Keflavik, with values for each month shown alongside May's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how May's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec7.87.27.26.25.0 m/s5.85.14.87.26.87.16.5
Data source: Keflavik May wind data, generated using information from the Copernicus Climate Change Service.

How May Weather in Keflavik Compares to Other Months

The weather in Keflavik changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of May's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Keflavik and find detailed weather information for every month.

May and January present contrasting weather patterns. In May, temperatures rise to an average of 7°C (44°F), with a maximum of 12°C (54°F), while January offers a chillier average of 2°C (36°F), peaking at 9°C (49°F). Precipitation levels are similar, with May experiencing 115 mm over 16 days and January slightly higher at 117 mm over 17 days. Moreover, humidity in May reaches 85%, compared to January's 80%, suggesting a fresher feel during the latter winter month. For more detailed insights into January weather, you can refer to Keflavik weather in January.

When comparing the weather in May and February, we observe a notable difference in temperatures and precipitation patterns. May typically experiences milder conditions, with average temperatures ranging from 0°C (33°F) to a maximum of 12°C (54°F), alongside relatively high humidity levels at 85%. In contrast, February is chillier, with temperatures ranging from a minimum of -9°C (16°F) to a maximum of 8°C (47°F), and a lower humidity of 77%. Precipitation is frequent in both months, with February receiving 126 mm (5.0 in) over 19 days and May slightly less at 115 mm (4.5 in) over 16 days. For more detailed information about February weather, you can refer to Keflavik weather in February.

In comparing the weather between March and May, May emerges as significantly warmer, with average temperatures rising from 2°C (37°F) in March to 7°C (44°F) in May. While both months experience similar levels of precipitation, with May seeing slightly more at 115 mm (4.5 in) compared to March's 110 mm (4.3 in), May enjoys fewer rainy days, averaging 16 days versus March's 18 days. Additionally, humidity is slightly higher in May at 85%, compared to 82% in March, creating a more humid environment as spring advances. For a more detailed overview, you can check Keflavik weather in March.

When comparing the weather of May and April, both months exhibit cool temperatures with April slightly chillier on average. In May, the minimum temperature hovers around 0°C (33°F), with an average of 7°C (44°F) and a maximum of 12°C (54°F), while April features a cooler minimum of -7°C (20°F) with an average of 5°C (41°F) and a maximum of 11°C (52°F). Precipitation levels are fairly high in both months, with May receiving 115 mm (4.5 in) over 16 days, slightly less than April's 133 mm (5.2 in) over 18 days. Humidity is also higher in May at 85%, compared to April's 80%. For more detailed insights, you can check out Keflavik weather in April.

In comparing the weather between May and June, it's evident that June brings slightly warmer temperatures, with daily averages rising from 7°C (44°F) in May to 9°C (48°F) in June. The minimum temperature increases from 0°C (33°F) to 4°C (39°F), while the maximum temperature climbs from 12°C (54°F) to 15°C (60°F). Additionally, June experiences a decrease in precipitation, with 87 mm (3.4 in) falling over 15 days compared to May's 115 mm (4.5 in) over 16 days. Humidity remains constant between the two months at 85%. To explore more about June's weather, you can visit Keflavik weather in June.

When comparing the weather in May and July, it's clear that July experiences milder temperatures. In May, temperatures range from a minimum of 0°C (33°F) to a maximum of 12°C (54°F), with an average of 7°C (44°F). In contrast, July's temperatures start at a minimum of 6°C (43°F) and peak at 19°C (66°F), yielding a more comfortable average of 11°C (52°F). Precipitation is higher in May, with 115 mm (4.5 in) falling over 16 days, compared to July's 78 mm (3.1 in) over 18 days. While humidity slightly increases from 85% in May to 87% in July, the overall weather in July tends to be milder and more pleasant for outdoor activities. For more details, you can check out Keflavik weather in July.

May and August present distinct weather patterns. In May, temperatures range from a chilly 0°C (33°F) to a mild 12°C (54°F), with an average temperature around 7°C (44°F). This month sees a significant amount of precipitation, totaling 115 mm (4.5 in) over 16 days, accompanied by high humidity levels at 85%. In contrast, August is warmer, with temperatures ranging from a minimum of 7°C (45°F) to a maximum of 16°C (62°F), and an average of 11°C (52°F). Precipitation in August is lower at 89 mm (3.5 in) over 13 days, with humidity slightly higher at 88%. This comparative overview highlights the transition from the cooler, wetter conditions of May to the milder, yet still damp, atmosphere of August. For more details, you can visit Keflavik weather in August.

In comparing the weather of May and September, both months exhibit similar humidity levels at 85%, contributing to a consistently damp atmosphere. However, May is generally cooler, with temperatures ranging from a minimum of 0°C (33°F) to a maximum of 12°C (54°F), while September sees slightly warmer averages, with minimums of 1°C (34°F) and maximums reaching 13°C (56°F). Additionally, September tends to experience more precipitation, totaling 171 mm (6.7 in) over 21 days, compared to May's 115 mm (4.5 in) spread across 16 days. This shift makes September a wetter month overall. For more detailed insights into September's climate, check Keflavik weather in September.

In May, temperatures range from a minimum of 0°C (33°F) to a maximum of 12°C (54°F), with an average of 7°C (44°F). The month sees approximately 115 mm (4.5 in) of precipitation over 16 days, maintaining a humidity level of 85%. In contrast, October experiences slightly cooler temperatures, with a minimum of -1°C (30°F) and an average temperature of 6°C (44°F), while also peaking at 12°C (53°F). Rainfall increases to about 119 mm (4.7 in) across 18 days, preserving the same high humidity level. For more specific details on the conditions during this month, you can refer to Keflavik weather in October.

In comparing the weather of May and November, May tends to be slightly warmer, with average temperatures around 7°C (44°F), compared to November's average of 4°C (39°F). While May experiences a minimum temperature of 0°C (33°F), November can drop to -4°C (25°F). Both months see significant precipitation; May averages 115 mm (4.5 in) over 16 days, while November has 119 mm (4.7 in) spread across 18 days, indicating a wetter late autumn. Humidity levels are relatively high in both months, but May is slightly more humid at 85% compared to November's 81%. For more details about November weather specifics, visit Keflavik weather in November.

May and December present contrasting weather conditions, with May typically enjoying milder temperatures and increased rainfall. In May, temperatures range from a minimum of 0°C (33°F) to a maximum of 12°C (54°F), with an average of 7°C (44°F). Precipitation is significant at 115 mm (4.5 in) over approximately 16 days, accompanied by high humidity levels at 85%. In contrast, December is colder, featuring temperatures that drop to a minimum of -6°C (21°F) and reach a maximum of 9°C (49°F), averaging at 2°C (37°F). The month has slightly more rainfall at 119 mm (4.7 in) over 18 days, but with a lower humidity of 80%. For a deeper look into December conditions, check out Keflavik weather in December.

Compare Keflavik's Climate with Cities Worldwide

Conclusion: What to Expect From May Weather in Keflavik

As May arrives in Keflavik, the landscape begins to shake off the chill of winter, with temperatures gradually warming and a noticeable increase in daylight. Although the average temperature hovers around a refreshing 7°C (44°F), chilly winds can still bring the occasional frosty night, making it essential to pack layers. The month is marked by increased precipitation, with about half the days experiencing some rain, contributing to the lush greenery that characterizes this time of year. Despite the dampness, the rising humidity adds a vibrant richness to the air, heralding the onset of summer and making it a unique month to explore the stunning beauty of Iceland. For more detailed insights, check Keflavik Climate.