Last updated: August 31, 2025
September in Longyearbyen, Svalbard and Jan Mayen is marked by a chilly climate, with maximum temperatures peaking at 8°C (46°F) and average readings around 2°C (35°F). As the month progresses, temperatures can dip as low as -10°C (15°F), creating a striking contrast between the crisp air and the surrounding landscapes. Rainfall is frequent, with 75 mm (3.0 in) of precipitation spread over 16 days, resulting in a humid environment characterized by nearly 99% humidity. This month serves as a transition into winter, making it a captivating time to experience the unique beauty and challenges of the Arctic environment.
September in Longyearbyen, Svalbard and Jan Mayen marks a noticeable transition in temperatures as the warmth of summer begins to fade. With minimums averaging -10°C (15°F) and highs peaking at 8°C (46°F), this month presents a crisp, invigorating chill compared to the milder days of August. The average temperature settles around 2°C (35°F), signaling the onset of autumn and the gradual approach of winter. As the landscape transforms, travelers can experience the beauty of changing foliage against a backdrop of northern lights in the twilight skies, capturing the essence of a unique Arctic climate.
As September unfolds in Longyearbyen, Svalbard, and Jan Mayen, it marks a notable shift in precipitation patterns. With 75 mm (3.0 in) of rain recorded over 16 days, September experiences the highest rainfall of the year, showcasing a clear transition from the warmer summer months. This spike in precipitation is strikingly higher than the preceding months, such as July and August, which received 53 mm (2.1 in) and 52 mm (2.0 in) respectively over fewer days. The increased frequency of rain not only enriches the landscape but also sets the stage for the impending colder months, as the region prepares to embrace the long Arctic winter.
In September, the humidity in Longyearbyen, Svalbard, and Jan Mayen remains impressively high at 99%, continuing the theme of elevated moisture levels that characterize the late summer and early fall months. This trend reflects a consistent pattern throughout the year, with humidity peaking during the colder months of January through August, where it often hovers around 98% to 101%. As the seasons transition, the drop in temperatures doesn’t significantly alter humidity levels, showcasing the Arctic region's chilly yet damp climate. Following September, a slight decrease to 97% is observed in October, but overall, the atmospheric moisture in this remote archipelago is a persistent feature of its stark, rugged beauty.
As summer fades into autumn, September in Longyearbyen sees a slight dip in UV exposure, with the UV Index dropping to 1, classified as low. This trend mirrors the gradual decline observed since the peak months of June and July, which boasted an index of 3. During September, the recommended burn time remains generous at 45 minutes, allowing for safe outdoor activities without the need for heavy sun protection. This pattern continues into October, reinforcing the notion of limited UV intensity in the region as winter approaches. For more details on the UV levels throughout the year, check out Longyearbyen UV Index.
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As the vibrant summer months fade away, September in Longyearbyen, Svalbard, and Jan Mayen welcomes a remarkable shift in daylight, offering 131 hours of sunshine—a gentle transition from the bright days of summer to the long nights of winter. This month's daylight marks a significant decrease from August's 307 hours, resonating with the gradual retreat of the midnight sun. The trend showcases a steady decline in available sunlight after a peak in May, where over 495 hours illuminated the Arctic landscape. As autumn sets in, residents and visitors alike can savor the crisp air and the enchanting changes in nature, all while preparing for the return of long, dark winter nights ahead.
In Longyearbyen, Svalbard and Jan Mayen, the likelihood of sunny weather undergoes notable fluctuations throughout the year. As summer peaks in May, the chances of sunshine rise significantly to 33%, but this warmth dwindles as the seasons shift. By September, the likelihood of sun drops to 14%, a slight improvement from the preceding months of August and July, which see even fewer sunlit days at 8% and 10% respectively. This pattern hints at a gradual transition into the darker months, yet September still offers a ray of hope for those yearning for a glimpse of sunshine before winter sets in.
As September arrives in Longyearbyen, Svalbard, and Jan Mayen, the lingering glow of summer gradually fades, revealing a significant shift in daylight hours. Following the continuous midnight sun of late spring and summer, which graced these regions with up to 24 hours of daylight, September presents a more subdued yet still substantial 14 hours of sunlight. This month marks a transition towards autumn, as daylight diminishes, hinting at the upcoming darkness of winter, where daylight plummets to zero in November and December. The consistent reduction from the vibrant days of summer serves as a poignant reminder of the polar cycle, where each season crafts a unique rhythm of light and shadow across these breathtaking Arctic landscapes.
As September arrives in Longyearbyen, Svalbard and Jan Mayen, the average wind speed gently shifts to 2.4 m/s (5 mph), representing a slight increase from the calm summer months of July and August. This subtle rise signals the transition into autumn, where winds begin to pick up but remain relatively mild compared to the gustier winter months ahead. Interestingly, the overall trend from spring through late summer showcases a gradual decline in wind speeds, hitting a low of 2.2 m/s (5 mph) in August. As the year progresses, particularly in the colder months, we see a return to stronger winds, with November's average reaching 3.7 m/s (8 mph), hinting at the impending winter's more challenging weather conditions. These patterns reflect the unique climatic rhythm of this remote Arctic environment, where each season brings its distinct character and wind dynamics.
Weather in Longyearbyen varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Longyearbyen, focusing on differences in temperature, rainfall, humidity, and UV levels.
In September, the weather is generally milder, with average temperatures around 2°C (35°F) and a maximum of 8°C (46°F). The month experiences significant precipitation with about 75 mm (3.0 in) falling over 16 days, alongside high humidity levels at 99%. In contrast, January is much colder, with average temperatures dropping to -12°C (11°F) and daytime highs reaching only 2°C (35°F). Precipitation decreases significantly to 35 mm (1.4 in) over just 7 days, and humidity remains high at 98%. For a more detailed look at January conditions, you can visit Longyearbyen weather in January.
In comparing the weather between September and February, it is clear that February is significantly colder, with average temperatures ranging from a minimum of -26°C (-15°F) to a maximum of only 2°C (36°F). In contrast, September enjoys slightly milder temperatures, where the minimum is -10°C (15°F) and the average rises to 2°C (35°F). Additionally, February receives less precipitation, measuring 47 mm (1.9 in) over 11 days, compared to September, which has a higher total of 75 mm (3.0 in) over 16 days. Both months exhibit high humidity levels of 99%, but the frigid air of February contributes to a harsher overall climate. For more specific details on February's conditions, explore Longyearbyen weather in February.
September and March present notably different weather conditions. In September, the temperatures range from a chilly -10°C (15°F) to a max of 8°C (46°F), with an average of 2°C (35°F). The month sees substantial precipitation, with 75 mm (3.0 in) falling over 16 days, accompanied by a high humidity of 99%. In contrast, March is significantly colder, featuring a minimum temperature of -30°C (-22°F) and an average of -14°C (7°F), with a maximum of only 2°C (37°F). Precipitation decreases to 38 mm (1.5 in) across 9 days, yet humidity remains at a constant 99%. For more detailed information on weather specifics in March, you can visit Longyearbyen weather in March.
September and April present stark contrasts in weather conditions. In September, temperatures range from a chilly minimum of -10°C (15°F) to a maximum of 8°C (46°F), with an average of 2°C (35°F). This month sees 75 mm (3.0 in) of precipitation over 16 days, accompanied by remarkably high humidity at 99%. In contrast, April is much colder, with temperatures dipping as low as -26°C (-14°F) and peaking at just 1°C (34°F), making the average a frigid -10°C (15°F). Precipitation is also lower in April at 38 mm (1.5 in) over 10 days, and while humidity is slightly lower at 98%, the biting cold makes it feel quite brisk. For a deeper look into April's weather, you can check Longyearbyen weather in April.
In comparing the weather of September and May, it's evident that September experiences milder temperatures, with an average of 2°C (35°F) compared to May's average of -4°C (25°F). While September has a higher maximum temperature of 8°C (46°F), May records a slightly lower minimum of -16°C (4°F), making it the colder month overall. Precipitation is also more frequent in September, with rain or snow occurring on 16 days and totaling 75 mm (3.0 in), while May sees only 35 mm (1.4 in) over 9 days. Humidity levels are quite high in both months, with September at 99% and May at 94%. For those interested in a detailed look at May weather, you can refer to Longyearbyen weather in May.
When comparing the weather in September and June, notable differences emerge. September features colder temperatures, with a minimum of -10°C (15°F) and an average of 2°C (35°F), contrasting with June's milder minimum of -2°C (29°F) and a similar average of 2°C (36°F). Rainfall is more frequent in September, with precipitation occurring on 16 days totaling 75 mm (3.0 in), compared to June's 8 days of lighter rain, accumulating just 31 mm (1.2 in). Additionally, September’s humidity remains at a high 99%, while June has slightly lower humidity at 95%. For those interested in more detailed June weather conditions, please refer to this link: Longyearbyen weather in June.
When comparing the weather in September and July, it's clear that July tends to be significantly warmer. In July, temperatures range from a minimum of 0°C (33°F) to a maximum of 16°C (61°F), with an average of 6°C (43°F). In contrast, September sees much cooler temperatures, with a minimum of -10°C (15°F) and a maximum of only 8°C (46°F), averaging at 2°C (35°F). Additionally, July experiences less precipitation at 53 mm (2.1 in) over 13 days, while September has higher precipitation levels at 75 mm (3.0 in) over 16 days, both months exhibiting 99% humidity. For a more detailed look at July’s weather, you can visit Longyearbyen weather in July.
September's weather is notably colder than August, with minimum temperatures plunging to -10°C (15°F) compared to August's milder minimum of 0°C (32°F). The average temperature in September is 2°C (35°F), falling significantly from August's average of 5°C (41°F), and the maximum temperature in September peaks at just 8°C (46°F), whereas August can reach up to 14°C (58°F). Additionally, September experiences more precipitation—75 mm (3.0 in) over 16 days—compared to August's 52 mm (2.0 in) over 10 days, and while humidity is slightly lower in September at 99%, it remains quite high overall. For those interested in August's specific conditions, additional details can be found here.
In September, the weather in Longyearbyen is characterized by a milder climate, with average temperatures around 2°C (35°F) and a maximum of 8°C (46°F). This month experiences substantial precipitation, totaling 75 mm (3.0 in) over 16 days, and humidity levels are exceptionally high at 99%.
By October, temperatures have dropped significantly, with a minimum of -15°C (5°F) and an average of -4°C (26°F). The precipitation decreases to 34 mm (1.4 in), falling over just 9 days, and humidity remains slightly lower at 97%. Overall, October presents a sharper transition into the winter months compared to the relatively mild September. For more detailed information, visit Longyearbyen weather in October.
In September, Longyearbyen experiences milder temperatures with a minimum of -10°C (15°F) and average highs around 8°C (46°F), making it the tail end of the summer season. The weather is quite damp, with precipitation recording 75 mm (3.0 in) over 16 days and humidity reaching a high of 99%. In contrast, November ushers in harsher winter conditions, featuring a significantly colder average temperature of -8°C (18°F) and a maximum of only 5°C (41°F), with lows dropping to -23°C (-9°F). This month also sees reduced precipitation levels at 46 mm (1.8 in) over just 12 days, while humidity remains slightly lower at 98%. For more detailed insights into November's weather, check out Longyearbyen weather in November.
In September, the weather starts to cool down, with temperatures ranging from a chilly -10°C (15°F) at night to an average of 2°C (35°F) during the day, peaking at a maximum of 8°C (46°F). This month experiences considerable precipitation, with about 75 mm (3.0 in) over 16 days and high humidity levels at 99%. In contrast, December brings even colder conditions, with temperatures dropping significantly to a minimum of -26°C (-14°F), an average of -9°C (16°F), and a maximum of just 1°C (33°F). Although December sees less precipitation at 53 mm (2.1 in) over 12 days, the humidity remains high at 98%. For more details about the distinct weather patterns in December, visit Longyearbyen weather in December.
As summer fades into fall, September in Longyearbyen presents a unique climate narrative. Experiencing a pronounced drop in temperatures, the month showcases chilly days, with an average hovering around freezing and nights plunging into frosty conditions. Unlike the milder summer months, September brings increased precipitation, with rain often interspersed with early snowfall, contributing to the region's dramatic scenery. The atmosphere feels notably heavier as humidity reaches a staggering 99%, wrapping the landscape in a damp embrace. For those eager to explore the breathtaking contrasts of Arctic weather, September offers a more subdued yet captivating experience. To learn more about how the weather evolves throughout the year, visit Longyearbyen Climate.