September Weather in Hafnarfjoerdur, Iceland

Last updated: March 17, 2025

September in Hafnarfjörður, Iceland brings a refreshing yet brisk transition into autumn, with maximum temperatures reaching 16°C (60°F) and dipping to a chilly -2°C (29°F) at night. The average temperature settles around a moderate 8°C (47°F), making it a month where layers become essential. With a high humidity level of 87%, the air is often crisp and damp. Visitors can expect substantial precipitation, with about 163 mm (6.4 in) of rain over approximately 22 days, painting the landscape in vibrant autumn hues while providing a dramatic backdrop for exploring this enchanting coastal town.

September Temperature in Hafnarfjoerdur

As September arrives in Hafnarfjörður, Iceland, temperatures begin to shift towards the cool embrace of autumn. With a minimum of -2°C (29°F) and a maximum around 16°C (60°F), the days are noticeably crisper compared to the balmy temperatures of summer, yet not as harsh as the deep winter months ahead. The average temperature stabilizes at 8°C (47°F), reflecting a transitional period where the summer's warmth gradually yields to the chill of fall. This month marks the beginning of a downward trend, foreshadowing the colder weather to come, but September's weather still invites exploration of the stunning Icelandic landscapes before winter fully sets in.

September Weather in Hafnarfjoerdur: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Hafnarfjoerdur, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec333335404449525247423634
Data source: Temperature data for Hafnarfjoerdur 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.

September Precipitation in Hafnarfjoerdur

In September, Hafnarfjörður experiences a notable increase in precipitation, receiving 163 mm (6.4 in) of rain over 22 days, making it one of the wettest months of the year. This surge marks a contrast to the drier summer months of July and August, where precipitation levels drop to 81 mm (3.2 in) and 90 mm (3.6 in), respectively. As autumn sets in, the shift toward wetter conditions signifies a transition, with September often characterized by more frequent rainfall, making the landscape lush and vibrant. This trend continues into the fall, as both October and November maintain high precipitation levels, reinforcing the notion that the wet season in Hafnarfjörður is just beginning.

September Precipitation Trends in Hafnarfjoerdur

The chart displays monthly precipitation patterns in Hafnarfjoerdur, with values for each month alongside September's data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September's conditions compare to those of other months.
JanFebMarAprMayJunJulAugSepOctNovDec118135105138124978190163111112114
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Hafnarfjoerdur

As summer transitions to autumn in Hafnarfjörður, Iceland, September brings a notable continuation of high humidity levels, maintaining a steady 87%, consistent with August's peak. This indicates a trend of elevated moisture in the air as the year progresses, with humidity gradually rising from 81% in April to 89% by October. The heightened humidity is characteristic of the region's climate, where the presence of water bodies and the ocean's influence contribute to a persistent dampness, creating a unique atmosphere as the crispness of fall begins to settle in. This continuity in humidity not only reflects the natural rhythms of Hafnarfjörður's weather but also enhances its scenic beauty, making it a captivating destination throughout the year.

September Average Humidity in Hafnarfjoerdur

This chart illustrates the average monthly humidity levels in Hafnarfjoerdur, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%85%81%83%82%86%87%87%88%85%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Hafnarfjoerdur

As September rolls in Hafnarfjoerdur, Iceland, the UV Index settles at 3, reflecting a moderate exposure category that warrants attention during outdoor activities. This marks a noticeable decline from the peak summer months, where July and August exhibited high to moderate indexes of 6 and 4, respectively. With a burn time of about 30 minutes, sun seekers should remain mindful of their skin’s sensitivity, especially as the days grow shorter and cooler. This transition signals the gradual return to lower UV levels typical of the autumn months, as seen with October's UV Index of 2. For detailed guidance on UV conditions throughout the year, check out the comprehensive resource at Hafnarfjoerdur UV Index.

Maximum UV Index Levels in Hafnarfjoerdur for September

The chart shows the monthly maximum UV Index (UVI) for Hafnarfjoerdur in September, 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: Hafnarfjoerdur September 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.

September Sunshine in Hafnarfjoerdur

September in Hafnarfjörður, Iceland, radiates with a delightful 206 hours of sunshine, marking a vibrant transition into autumn. As summer fades, the sun's embrace begins to wane, evident in the notable decrease from 344 hours in May to September's gentle glow. The sunny days of June and July, with their peaks of 338 and 316 hours, create a rich backdrop, making September feel like a graceful encore before the soft light of October settles in with just 147 hours. The gradual decline after the summer solstice reflects the natural rhythm of Arctic seasons, inviting residents and visitors alike to savor the last warm rays before winter's approach.

Monthly Sunshine Duration in Hafnarfjoerdur: September Highlighted

The September sunshine duration represents the total number of hours Hafnarfjoerdur experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec41h90h197h215h344h338h316h297h206h147h78h29h
Data source: Hafnarfjoerdur September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Hafnarfjoerdur During September

In Hafnarfjörður, Iceland, the likelihood of sunny weather takes a noticeable dip as summer gives way to autumn. September, with a mere 14% chance of sunshine, continues this trend from the preceding months, where the peak summer months of June (15%) and July (11%) offered little brightness as well. In fact, September falls among the lower range of sunny probabilities, only slightly above August’s dismal 8%. While this coastal town has its moments of brightness, the transitioning season tends to favor cloudy skies over rays of sunshine, reminding visitors that even in Iceland, nature reigns supreme.

Percentage of Sunny Days in September in Hafnarfjoerdur

The chart illustrates the percentage of sunny days in Hafnarfjoerdur throughout the year, with September 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 Hafnarfjoerdur experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec30%16%16%25%42%15%11%8%14%27%22%18%
Data source: Hafnarfjoerdur September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Hafnarfjoerdur in September

As summer wanes, September in Hafnarfjörður, Iceland, offers a gentle transition with approximately 12 hours of daylight. Following the long, sunlit days of late summer, this shift marks a significant decrease from the 18 hours in May and 20 hours in June. The brightness begins to soften as autumn approaches, signaling shorter days ahead, with October dipping to just 9 hours of daylight. This natural rhythm highlights the change in seasons, where the vibrant energy of summer gradually gives way to the serene, reflective tones of fall, inviting residents and visitors alike to embrace the beauty of life under the shifting skies.

Average Daylight Hours in Hafnarfjoerdur for September

The chart illustrates the variation in daylight duration in Hafnarfjoerdur throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec5h 32m8h 34m11h 50m15h 9m18h 28m20h 46m19h 26m16h 12m12h 55m9h 39m6h 26m4h 21m
Data source: Hafnarfjoerdur daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Hafnarfjoerdur

In Hafnarfjörður, Iceland, the September winds carry a refreshing momentum, picking up slightly to an average speed of 4.9 m/s (11 mph), more akin to the breezy days of earlier months rather than the calmer summer air. As we transition from summer's gentle 3.5 m/s (8 mph) in August, there's a noticeable increase in activity, hinting at the approaching autumn. This shift is part of a broader trend observed throughout the year; while winter months like January and February maintain a steady 5.0 m/s, spring and summer see a gradual decrease to softer winds. However, just as winter returns, September seems to bridge the seasons with a lively gust, making it a perfect time to experience the unique charm of Iceland's coastal landscape.

Average September Wind Speed in Hafnarfjoerdur

The chart displays monthly wind speed patterns in Hafnarfjoerdur, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec5.05.04.74.33.54.13.63.54.9 m/s4.54.64.3
Data source: Hafnarfjoerdur September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Hafnarfjoerdur Compares to Other Months

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

In September, the weather begins to cool down as temperatures range from a minimum of -2°C (29°F) to an average of 8°C (47°F), and can peak at 16°C (60°F). The month sees considerable precipitation, with 163 mm (6.4 in) falling over 22 days, contributing to a high humidity level of 87%. In contrast, January is significantly colder, with temperatures dropping to a minimum of -11°C (13°F) and averaging just 1°C (33°F), reaching a maximum of 10°C (51°F). Precipitation is lower at 118 mm (4.6 in) across 16 days, and humidity remains relatively high at 84%. For more details on January weather specifically in Hafnarfjörður, you can find additional information here: Hafnarfjoerdur weather in January.

September and February present contrasting weather patterns. In September, temperatures range from a minimum of -2°C (29°F) to a maximum of 16°C (60°F), with an average of 8°C (47°F), accompanied by high humidity at 87% and significant precipitation of 163 mm (6.4 in) over 22 days. In contrast, February is colder, with temperatures dropping to a minimum of -18°C (0°F) and only reaching a maximum of 9°C (48°F), resulting in a much lower average of 1°C (34°F). Precipitation is slightly less in February at 135 mm (5.3 in) across 19 days, and humidity remains somewhat lower at 82%. For more detailed insights, visit Hafnarfjoerdur weather in February.

When comparing the weather in September and March, September typically offers milder temperatures, ranging from a minimum of -2°C (29°F) to an average of 8°C (47°F) and a maximum of 16°C (60°F). In contrast, March tends to be colder, with temperatures dipping to a low of -11°C (13°F) and averaging around 2°C (35°F), reaching a maximum of 10°C (49°F). Precipitation is more frequent in September, with 163 mm (6.4 in) falling over 22 days, compared to March's 105 mm (4.1 in) across 18 days. Humidity levels are similarly high in both months, with September at 87% and March slightly lower at 85%. For a detailed look, check out Hafnarfjoerdur weather in March.

When comparing the weather in September and April, we notice distinct contrasts in temperature and precipitation. September generally offers milder temperatures, with averages around 8°C (47°F) and maximums reaching 16°C (60°F), while April is cooler, with an average of 4°C (40°F) and highs up to 13°C (56°F). In terms of precipitation, September experiences more rain, totaling 163 mm (6.4 in) over 22 days, compared to April’s 138 mm (5.4 in) over 17 days. Additionally, September’s humidity is higher at 87%, whereas April has a slightly lower humidity level of 81%. For more detailed information about the weather conditions in Hafnarfjörður during April, you can check this link: Hafnarfjoerdur weather in April.

When comparing the weather in September and May, both months exhibit cool temperatures but September tends to be slightly milder. In September, the average temperature hovers around 8°C (47°F), with a maximum of 16°C (60°F), whereas May shows an average of 7°C (44°F) and a peak of 15°C (59°F). Precipitation is more significant in September, with 163 mm (6.4 in) over 22 days compared to May's 124 mm (4.9 in) across 18 days. Additionally, humidity is slightly higher in September at 87%, compared to 83% in May. For further details on May weather, you can visit Hafnarfjoerdur weather in May.

September and June present noticeable differences in weather patterns, particularly in temperature and precipitation. In September, temperatures range from a low of -2°C (29°F) to a high of 16°C (60°F), with an average of 8°C (47°F). This month also experiences significant wetness, with approximately 163 mm (6.4 in) of precipitation over 22 days and humidity levels at 87%. In contrast, June is slightly warmer, with temperatures ranging from 2°C (36°F) to 19°C (66°F) and an average of 9°C (49°F). The month is drier with only about 97 mm (3.8 in) of precipitation over 17 days and a somewhat lower humidity at 82%. For more detailed information on June weather, you can check Hafnarfjoerdur weather in June.

In comparing the weather of September and July, September is notably cooler, with average temperatures ranging from a minimum of -2°C (29°F) to a maximum of 16°C (60°F). In contrast, July enjoys warmer conditions, boasting a minimum temperature of 3°C (38°F) and going up to a maximum of 23°C (74°F). September also experiences significantly more precipitation, with 163 mm (6.4 in) over 22 days, compared to July's 81 mm (3.2 in) over 16 days. Humidity levels remain relatively similar, with September at 87% and July at 86%. For a more detailed look at July weather conditions, you can visit Hafnarfjoerdur weather in July.

In comparing the weather of September and August, September tends to be cooler with average temperatures ranging from a minimum of -2°C (29°F) to a maximum of 16°C (60°F), while August sees milder conditions with temperatures ranging from a minimum of 4°C (40°F) to a maximum of 19°C (66°F). Additionally, September experiences significantly more precipitation, totaling 163 mm (6.4 in) over 22 days compared to August's 90 mm (3.6 in) over 14 days. Interestingly, despite the changes in temperature and rainfall, both months share a consistent humidity level of 87%. For more detailed information, you can check Hafnarfjoerdur weather in August.

September and October exhibit noticeable differences in weather conditions. In September, temperatures range from a minimum of -2°C (29°F) to a maximum of 16°C (60°F), with an average of 8°C (47°F). This month also experiences significant rainfall, totaling 163 mm (6.4 in) over 22 days, along with a high humidity level of 87%. Conversely, October sees cooler temperatures, with a minimum of -5°C (23°F), an average of 5°C (42°F), and a maximum of 13°C (55°F). Precipitation decreases to 111 mm (4.4 in) spread over 17 days, while humidity rises slightly to 88%. For more detailed information on the weather in this month, you can refer to Hafnarfjoerdur weather in October.

September typically presents a mild transition from summer to autumn, with average temperatures ranging from a low of -2°C (29°F) to a high of 16°C (60°F). However, this month is characterized by significant precipitation, with about 163 mm (6.4 in) falling over 22 days, contributing to a high humidity level of 87%. In contrast, November brings a notable drop in temperatures, with averages between -9°C (16°F) and 11°C (52°F). Despite experiencing less rainfall, totaling 112 mm (4.4 in) spread over 15 days, the humidity remains relatively similar at 85%. For those interested in more detailed insights, Hafnarfjoerdur weather in November offers a comprehensive look at the climatic conditions in that month.

In comparing the weather between September and December, there is a noticeable drop in temperature as we transition into winter. September averages around 8°C (47°F), with maximum temperatures reaching 16°C (60°F), while December sees a colder average of 1°C (34°F), peaking at just 10°C (50°F). Precipitation is also significant in both months, with September experiencing 163 mm (6.4 in) over 22 days, compared to December's 114 mm (4.5 in) over 16 days. Humidity remains relatively high in both months, at 87% in September and slightly lower at 84% in December. For a more in-depth look at December conditions, you can visit Hafnarfjoerdur weather in December.

Compare Hafnarfjoerdur's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Hafnarfjoerdur

As September unfolds in Hafnarfjörður, the weather begins to shift noticeably from the summer’s warmth, welcoming a cooler embrace, with daily temperatures dropping significantly. This month is characterized by increased precipitation, with rain gracing the area on nearly three-quarters of the days, coupled with humidity levels that linger at a high 87%. The crisp air and occasional chill hint at the arrival of autumn, marking a dramatic transition from the balmy days of summer. For a more detailed look at the changing climate in Hafnarfjörður, check out Hafnarfjoerdur Climate.