September Weather in Grindavik, Iceland

Last updated: March 17, 2025

In Grindavik, Iceland, September greets visitors with a cool coastal climate, featuring an average temperature of 9°C (49°F). The month experiences maximum highs of 13°C (56°F) and minimum lows dipping to 2°C (35°F), making it essential to dress in layers. With precipitation totaling 159 mm (6.2 in) over approximately 20 days, the air remains notably humid at 85%, creating a crisp atmosphere interspersed with frequent showers. This combination of cooler temperatures and high humidity contributes to the region's lush landscapes, perfect for exploration and experiencing Iceland's natural beauty.

September Temperature in Grindavik

In September, Grindavik, Iceland, transitions into cooler weather, with temperatures signaling the approach of autumn. The month sees minimums dropping to about 2°C (35°F), while average temperatures hover around 9°C (49°F) and maximums peak at a mild 13°C (56°F). This gradual shift from the more temperate summer months creates a refreshing atmosphere, inviting visitors to explore the stunning landscapes without the chill of winter yet creeping in. As the month progresses, the cool air enhances the vibrant hues of the surrounding nature, making it an excellent time for outdoor adventures and geothermal relaxation. Overall, September serves as a delightful bridge between summer's warmth and winter's embrace in this enchanting corner of Iceland.

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

The chart illustrates September temperature patterns in Grindavik, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec373738414448525248444038
Data source: Temperature data for Grindavik generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Grindavik

September marks a notable increase in precipitation for Grindavik, Iceland, with 159 mm (6.2 in) of rainfall measured over 20 days. This surge contrasts sharply with the drier summer months, where June and July saw considerably lower totals of 82 mm (3.2 in) and 77 mm (3.0 in), respectively. The increased rainfall sets the tone for autumn, reminding residents that summer's reprieve is fleeting. As the month transitions into October, with its own substantial 131 mm (5.2 in) expected over 17 days, September's downpours signal the onset of a wetter season, reinforcing the region's dynamic and changeable climate.

September Precipitation Trends in Grindavik

The chart displays monthly precipitation patterns in Grindavik, 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.
JanFebMarAprMayJunJulAugSepOctNovDec124138120134113827788159131128127
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Grindavik

In September, Grindavik, Iceland, experiences a comforting humidity level of 85%, maintaining the trend of high moisture typical of the summer months. Following the sweltering heights of 88% in August, the humidity slightly retreats but remains consistently elevated as the region transitions into autumn. Over the year, a distinct pattern emerges, showcasing a peak in humidity during the summer, particularly in July and August, before gradually decreasing into the fall and winter months. This steady atmosphere not only enriches the vibrant landscapes but also contributes to the unique ecological balance of this coastal town.

September Average Humidity in Grindavik

This chart illustrates the average monthly humidity levels in Grindavik, 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.
JanFebMarAprMayJunJulAugSepOctNovDec80%77%82%80%85%85%87%88%85%85%81%80%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Grindavik

As summer fades into autumn, September in Grindavik, Iceland, showcases a UV Index of 3, placing it in the moderate exposure category. This slight dip from the peak summer months of June and July, where the index reached 6, reflects the transitioning season, allowing for 30 minutes of midday sun before risk increases. With the UV Index gradually declining as the year progresses—dropping to 2 in October and 1 by November—it's clear that September offers a balanced opportunity for outdoor activities while still being mindful of sun safety. Discover more about the UV trends throughout the year at Grindavik UV Index.

Maximum UV Index Levels in Grindavik for September

The chart shows the monthly maximum UV Index (UVI) for Grindavik 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: Grindavik 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 Grindavik

As September dawns in Grindavik, Iceland, the sunlight begins to retreat after the vibrant summer months, yet it still offers a generous 203 hours of daylight. This marks a significant dip from the peak of 336 hours in June, but it's a continuation of a sunny trend established in July and August. While the transition into autumn is evident, with October's 138 hours promising stark contrast, September serves as a gentle reminder of summer's warmth, providing a perfect blend of lingering daylight and the crisp freshness of fall. The gradual decrease in sunlight, from the 324 hours in May to the 78 hours in November, showcases the rhythmic beauty of Iceland's seasonal shifts, each month painting a unique experience for residents and visitors alike.

Monthly Sunshine Duration in Grindavik: September Highlighted

The September sunshine duration represents the total number of hours Grindavik 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.
JanFebMarAprMayJunJulAugSepOctNovDec45h91h187h204h324h336h296h286h203h138h78h31h
Data source: Grindavik September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Grindavik During September

In Grindavik, Iceland, September presents a modest 15% chance of sunny weather, which reflects a broader trend of fluctuating sunlight throughout the year. After experiencing a peak in May, where sunny days reach nearly half the time, the summer months show a significant drop in sunlight, with July and August witnessing the lowest chances. This decline hints at the impending transition to autumn, as the sun begins to retreat and clouds become more prevalent. Notably, while September offers limited sunshine compared to the earlier months, it still surpasses several other winter months like March and June, hinting at the lingering warmth of summer before the colder seasons take hold.

Percentage of Sunny Days in September in Grindavik

The chart illustrates the percentage of sunny days in Grindavik 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 Grindavik experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec28%17%16%25%49%19%13%12%15%27%23%21%
Data source: Grindavik September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Grindavik in September

As September rolls into Grindavik, Iceland, the lingering warmth of summer gradually yields to the encroaching autumn. With 12 hours of daylight, this month marks a gentle transition, showcasing a notable decrease from July’s peak of 19 hours. The daylight hours dip further from the vibrant 16 hours of August, suggesting the sun's trajectory is now shifting more dramatically. As the year progresses, the days continue to shorten, but September's balanced glow invites a unique blend of summer remnants and autumn's beginnings, making it a captivating time for exploration in this stunning coastal town.

Average Daylight Hours in Grindavik for September

The chart illustrates the variation in daylight duration in Grindavik throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec5h 37m8h 36m11h 50m15h 7m18h 23m20h 35m19h 19m16h 10m12h 54m9h 41m6h 30m4h 29m
Data source: Grindavik daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Grindavik

As summer fades and autumn approaches, September in Grindavik, Iceland, welcomes a noticeable shift in wind patterns. The average wind speed rises to 7.8 m/s (17 mph), marking a brief uptick from the gentle summer breezes experienced in July and August. This increase signals the onset of more dynamic weather, a trend that continues into the fall. In comparison, the preceding months show a gradual decline in wind speeds, with May and July experiencing the calmest conditions at about 5.3 to 5.4 m/s (12 mph). Notably, September's winds are a prelude to the colder months ahead, where speeds stabilize around 7.6 to 8.3 m/s (17 to 19 mph), creating a brisk atmosphere ideal for the whispering tales of Iceland’s rugged landscapes.

Average September Wind Speed in Grindavik

The chart displays monthly wind speed patterns in Grindavik, 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.
JanFebMarAprMayJunJulAugSepOctNovDec9.19.17.76.85.46.45.35.77.8 m/s7.68.37.6
Data source: Grindavik September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Grindavik Compares to Other Months

The weather in Grindavik 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 Grindavik and find detailed weather information for every month.

In September, the weather in Grindavik is relatively mild, with temperatures ranging from a minimum of 2°C (35°F) to a maximum of 13°C (56°F) and an average of 9°C (49°F). The month is characterized by frequent rainfall, receiving about 159 mm (6.2 in) over approximately 20 days, along with a high humidity level of 85%. In contrast, January experiences much colder temperatures, with a minimum of -5°C (23°F) and an average of 3°C (37°F), peaking at 10°C (50°F). Although January sees less precipitation at 124 mm (4.9 in) over 18 days, the lower humidity of 80% makes the cold feel more biting. For a detailed look at January weather conditions, you can check out Grindavik weather in January.

September and February showcase distinct weather patterns, with September generally being milder and wetter. In September, temperatures range from a minimum of 2°C (35°F) to a maximum of 13°C (56°F), averaging around 9°C (49°F). This month brings significant rainfall, with 159 mm (6.2 in) of precipitation over approximately 20 days, alongside higher humidity levels of 85%. In contrast, February experiences colder conditions, with temperatures dipping to a minimum of -8°C (19°F) and a maximum of 9°C (48°F), averaging 3°C (37°F). Although February sees slightly less precipitation at 138 mm (5.4 in) over the same number of rainy days, the humidity is lower at 77%. For more details on February's weather, you can check Grindavik weather in February.

When comparing the weather in September and March, it's clear that September offers milder temperatures with an average of 9°C (49°F), while March tends to be colder, averaging just 3°C (38°F). In September, temperatures can reach a maximum of 13°C (56°F), whereas March peaks at 8°C (47°F). Both months see similar levels of precipitation, with September receiving 159 mm (6.2 in) and March totaling 119 mm (4.7 in), spread over about 20 days in each month. Humidity is slightly higher in September at 85%, compared to 82% in March. For more specific insights on March weather in the region, you can check Grindavik weather in March.

In comparing the weather of September and April, we observe that September tends to be milder, with average temperatures ranging from 2°C (35°F) at night to a maximum of 13°C (56°F) during the day. In contrast, April is generally colder, with temperatures dipping as low as -6°C (21°F) and peaking at 10°C (51°F).

Precipitation also varies slightly; September receives about 159 mm (6.2 in) over 20 days, while April has 134 mm (5.3 in) across 19 days. Additionally, the humidity in September averages at 85%, compared to 80% in April, suggesting a slightly drier feel during the latter month. For more detailed information, you can check Grindavik weather in April.

When comparing the weather in September and May, both months exhibit relatively cool temperatures with minimal variation. September boasts slightly warmer averages, with minimums around 2°C (35°F) and maximums reaching 13°C (56°F), while May has a minimum of 1°C (34°F) and a maximum of 12°C (54°F). Precipitation is more pronounced in September, accumulating 159 mm (6.2 in) over 20 days, compared to May's 113 mm (4.4 in) over 16 days. Interestingly, both months share an identical humidity level of 85%, contributing to a damp atmosphere. For more specific details about May weather in Grindavik, visit Grindavik weather in May.

When comparing the weather in September to that of June, several notable differences emerge. In September, temperatures range from a chilly minimum of 2°C (35°F) to a maximum of 13°C (56°F), while June sees slightly warmer conditions with temperatures dipping to 4°C (39°F) and rising to 15°C (58°F). Precipitation is significantly higher in September, totaling 159 mm (6.2 in) over 20 days, compared to June, which experiences 82 mm (3.2 in) over just 15 days. Despite the variations, both months share a consistent humidity level of 85%. For more details on June weather specifically, you can refer to this link: Grindavik weather in June.

In comparing the weather of September to that of July, September tends to be cooler with a minimum temperature of 2°C (35°F) and an average of 9°C (49°F), while July's temperatures range from a minimum of 6°C (44°F) to an average of 11°C (52°F). Additionally, September experiences significantly higher precipitation, totaling 159 mm (6.2 in) over 20 days, in contrast to July's 77 mm (3.0 in) across 16 days. Both months have similar humidity levels, hovering around 85% in September and 87% in July. For more detailed insights regarding July weather, you can visit Grindavik weather in July.

In comparing the weather of September and August, we can see a notable shift in temperature and precipitation patterns. September experiences cooler temperatures with a minimum of 2°C (35°F) and an average of 9°C (49°F), while August has a milder range, with temperatures dipping to a minimum of 7°C (46°F) and averaging 11°C (52°F). Additionally, September is significantly wetter, receiving 159 mm (6.2 in) of precipitation over 20 days compared to August’s 88 mm (3.5 in) across 13 days. The humidity remains relatively high in both months, with September at 85% and August slightly higher at 88%. For more details on the weather in August, you can check Grindavik weather in August.

September and October exhibit a noticeable shift in weather conditions. In September, temperatures range from a minimum of 2°C (35°F) to a maximum of 13°C (56°F), with an average of 9°C (49°F) and a total precipitation of 159 mm (6.2 in) over 20 days, maintaining high humidity at 85%. In contrast, October sees cooler temperatures, with a minimum of -1°C (31°F), an average of 7°C (44°F), and a maximum of 11°C (53°F). Precipitation decreases slightly to 131 mm (5.2 in), occurring over 17 days, while humidity remains consistent at 85%. For a detailed look at what to expect, you can check out the Grindavik weather in October.

In September, the weather tends to be milder, with average temperatures ranging from a minimum of 2°C (35°F) to a maximum of 13°C (56°F) and averaging 9°C (49°F). The month is characterized by higher precipitation, with 159 mm (6.2 in) of rain across 20 days, and a humidity level of 85%. By contrast, November brings colder temperatures, with an average of 4°C (40°F) and a maximum of 10°C (51°F). Notably, November sees slightly less precipitation at 128 mm (5.0 in) over 19 days, alongside lower humidity at 81%. For more specific weather details, check out Grindavik weather in November.

September and December in Grindavik exhibit notable differences in weather patterns. September generally experiences milder temperatures, with an average of 9°C (49°F) and maximums reaching 13°C (56°F), while December temperatures drop significantly, averaging around 3°C (38°F) and peaking at 10°C (49°F). Precipitation in September is higher, totaling 159 mm (6.2 inches) over 20 days, compared to December's 127 mm (5.0 inches) across 18 days. Humidity levels are relatively high in both months, with September at 85% and December slightly lower at 80%. For more detailed insights, refer to Grindavik weather in December.

Compare Grindavik's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Grindavik

As September rolls into Grindavik, the weather shows a distinct transition from the vibrant summer months to the crispness of autumn. Temperatures dip significantly, bringing a refreshing chill that invites visitors to explore the rugged beauty of Iceland's landscape. While rainfall becomes more frequent, adding a serene ambiance to the scenery, the overall humidity remains high, creating a unique atmospheric experience. This month serves as a bridge, where lingering warmth gives way to cooler days and vibrant fall colors, making it an ideal time for those seeking a tranquil yet captivating Icelandic adventure. For a deeper understanding of how September fits into the broader climate spectrum, visit Grindavik Climate.