September Weather in Oslo, Norway

Last updated: August 27, 2025

September in Oslo, Norway, showcases a dynamic transition from summer warmth to the crisp beginnings of fall. With maximum temperatures reaching up to 25°C (77°F) and an average hovering around 12°C (53°F), the month offers a mild climate for outdoor enthusiasts. However, as autumn approaches, the minimum temperatures can dip to 1°C (35°F), urging residents to transition to warmer attire. The city experiences 106 mm (4.2 in) of precipitation over 13 days, contributing to the lush landscape while creating a notably humid atmosphere at 86%. This blend of warmth and moisture paints September as a vibrant month to explore Oslo's natural and cultural treasures.

September Temperature in Oslo

As September arrives in Oslo, the city begins to transition from the warmth of summer to the crispness of autumn. With temperatures ranging from a minimum of 1°C (35°F) to a maximum of 25°C (77°F), the month offers a delightful average of 12°C (53°F). This gradual shift reflects a retreat from the highs of summer, yet it still provides plenty of opportunities for outdoor activities and exploration. As the foliage starts to change, the comfortable weather encourages locals and visitors alike to enjoy the vibrant streets and picturesque parks before the chill of October sets in.

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

The chart illustrates September temperature patterns in Oslo, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Oslo, September typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec272733415161636053443628
Data source: Temperature data for Oslo 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 Oslo

As September arrives in Oslo, the city experiences a noteworthy increase in precipitation, with an average of 106 mm (4.2 in) over 13 days. This surge marks a transition from the late summer months, where rainfall was abundant but lower, with August recording 100 mm (3.9 in). September's rain sets the stage for the wetter months ahead, as October sees an even higher average of 130 mm (5.1 in). The shift also reflects a notable pattern of increased rainfall, as Oslo moves from its relatively drier summer to the autumn months, highlighting the dynamic climate of this beautiful Norwegian capital.

September Precipitation Trends in Oslo

The chart displays monthly precipitation patterns in Oslo, 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. In Oslo, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec606465389086103100106130107107
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Oslo

In September, Oslo experiences a noticeable rise in humidity, with levels climbing to 86% following the slightly drier summer months. This uptick reflects a gradual transition from the more comfortable summer humidity of 71% to 77% in June through August. As autumn sets in, the city's humidity begins to echo the moisture-rich winter months, with October's levels returning to 92%. This trend underscores Oslo’s climatic shift, where the crisp air of early fall is soon enveloped by the lingering dampness characteristic of the winter ahead, preparing the city for the inevitable chill and moisture that follow.

September Average Humidity in Oslo

This chart illustrates the average monthly humidity levels in Oslo, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Oslo is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec94%92%89%82%73%71%72%77%86%92%93%93%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Oslo

As September arrives in Oslo, the UV Index gently recedes to 4, marking a transition from the summer's high levels. This moderate rating indicates a slightly reduced risk for sunburn, with a recommended burn time of 30 minutes. After the peak summer months of June and July, when the UV Index reached 7, September reminds residents and visitors alike to remain cautious but allows for more comfortable outdoor activities without the heightened sun exposure. This shift serves as a reminder of the changing seasons, encouraging people to savor the mild autumn days while still being mindful of UV protection. For more details, check out the Oslo UV Index.

Maximum UV Index Levels in Oslo for September

The chart shows the monthly maximum UV Index (UVI) for Oslo 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. In September, the maximum UV index in Oslo typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec123457754211
Data source: Oslo 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 Oslo

As summer gracefully transitions into autumn, September in Oslo, Norway, brings a vibrant yet mellow change in sunshine hours. With 267 hours of sunlight, September reflects a noticeable decline from the sun-drenched summer months, where July boasts an impressive 466 hours. This month serves as a gentle reminder of nature's rhythm, offering a warm farewell to the bright days of summer while still providing a generous amount of sunlight compared to the dimmer winter months ahead. As daylight diminishes in October to 210 hours, the crisp air and golden foliage create an enchanting atmosphere, marking the shift to a new season and inviting residents and visitors alike to savor every sunbeam.

Monthly Sunshine Duration in Oslo: September Highlighted

The September sunshine duration represents the total number of hours Oslo 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.
JanFebMarAprMayJunJulAugSepOctNovDec89h175h286h369h404h441h466h390h267h210h127h93h
Data source: Oslo September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Oslo During September

In Oslo, September marks the transition into autumn, and with it, the chance of sunny weather dips to 26%. This decrease in sunshine follows a summer peak, with July boasting the highest likelihood of clear skies at 43%. After a promising spring where April shines with 56% sunny days, the trend reveals a slow but steady decline as the city braces for the cooler months. August continues this downward trend with 33%, leading into September's modest offering of sunshine. This gradual shift underscores the characteristic unpredictability of Nordic weather, inviting locals and visitors alike to embrace the fleeting sunny moments before the winter chill sets in.

Percentage of Sunny Days in September in Oslo

The chart illustrates the percentage of sunny days in Oslo 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 Oslo experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec32%42%39%56%27%36%43%33%26%27%21%25%
Data source: Oslo September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Oslo in September

As September unfolds in Oslo, the daylight hours begin a gentle decline from the glorious heights of summer. With 12 hours of daylight, the month marks a transition from the vibrant, sun-soaked days of June and July, which bask in up to 18 hours of light. This gradual reduction reflects the rhythm of the changing seasons, as the golden hues of fall start to replace the long, bright days of summer. Following September, daylight continues to wane, dipping to just 10 hours in October, and further into the darker months. The shift from the radiant burst of summer to the cozy embrace of autumn is beautifully captured in September, inviting a reflective pause as nature transitions around us.

Average Daylight Hours in Oslo for September

The chart illustrates the variation in daylight duration in Oslo throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec6h 47m9h 8m11h 51m14h 38m17h 13m18h 43m17h 54m15h 30m12h 47m10h 3m7h 28m5h 58m
Data source: Oslo daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Oslo

As September arrives in Oslo, Norway, the city experiences a gentle breeze with an average wind speed of 2.5 m/s (6 mph). This month marks a subtle transition from the warmer summer winds, which have been somewhat consistent yet slightly slower, with July and August hovering around 2.2 to 2.5 m/s. As autumn approaches, the wind begins to pick up slightly into October, reaching an average of 3.2 m/s (7 mph). Notably, while September’s winds reflect a slight decrease from the spring peak of 3.0 m/s in April, they remain mild, setting a pleasant tone for the changing scenery. This gradual shift illustrates Oslo's characteristic seasonal rhythm, blending tranquility with the onset of cooler weather.

Average September Wind Speed in Oslo

The chart displays monthly wind speed patterns in Oslo, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.62.62.73.02.42.42.22.52.5 m/s3.22.62.3
Data source: Oslo September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Oslo Compares to Other Months

Weather in Oslo varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Oslo, focusing on differences in temperature, rainfall, humidity, and UV levels.

September weather in Oslo is characterized by mild temperatures, ranging from a minimum of 1°C (35°F) to a maximum of 25°C (77°F), with an average of 12°C (53°F). The month experiences relatively high humidity at 86% and receives about 106 mm (4.2 in) of precipitation spread across 13 days. In contrast, January is much colder, with temperatures dipping to a minimum of -18°C (-1°F) and averaging -3°C (27°F), peaking at 9°C (49°F). While January sees lower precipitation levels at 60 mm (2.4 in) over 9 days, the humidity is slightly higher at 94%. For more details on January weather, check out Oslo weather in January.

September and February present stark contrasts in weather patterns. In September, temperatures range from a minimum of 1°C (35°F) to a maximum of 25°C (77°F), with an average of 12°C (53°F). This month experiences considerable precipitation, totaling 106 mm (4.2 in) over 13 days, and a humidity level of 86%. In contrast, February is much colder, with temperatures dipping as low as -20°C (-4°F) and averaging -3°C (27°F), peaking at 9°C (49°F). February sees less precipitation, at 64 mm (2.5 in) across 10 days, but the humidity is slightly higher at 92%. For more detailed information, check out Oslo weather in February.

When comparing the weather in September and March, significant differences emerge. September enjoys a milder climate with average temperatures ranging from 1°C to a maximum of 25°C, while March is much colder, with temperatures dipping as low as -18°C. Precipitation is more abundant in September, totaling 106 mm over 13 days, compared to March’s 65 mm over just 9 days. Humidity levels are relatively similar, with September at 86% and March slightly higher at 89%. For more detailed insights about the weather in March, you can check Oslo weather in March.

When comparing the weather in September and April, clear differences emerge in both temperature and precipitation. September experiences milder temperatures, with averages around 12°C (53°F) and highs reaching up to 25°C (77°F), while April is cooler, averaging just 5°C (41°F) with a minimum temperature as low as -12°C (11°F). Additionally, September tends to be wetter, with 106 mm (4.2 in) of precipitation over 13 days, compared to April's 38 mm (1.5 in) across only 6 days. Both months exhibit high humidity levels, though September is slightly higher at 86% compared to April’s 82%. For more specific details, you can check Oslo weather in April.

In September, the weather in Oslo tends to be milder, with average temperatures around 12°C (53°F) and maximums reaching up to 25°C (77°F). The month experiences a fair amount of rain, with 106 mm (4.2 in) falling over approximately 13 days and humidity levels peaking at 86%. In contrast, May has cooler temperatures, averaging 10°C (51°F) with a maximum of 29°C (85°F) but experiencing lower minimums of -3°C (26°F). With an average precipitation of 90 mm (3.5 in) over 12 days and reduced humidity at 73%, May offers a distinctively fresher feel. For further details, you can visit Oslo weather in May.

In September, the weather is generally cooler with temperatures ranging from a minimum of 1°C (35°F) to a maximum of 25°C (77°F), and an average of 12°C (53°F). The month experiences significant rainfall, accumulating 106 mm (4.2 in) over 13 days, and the humidity is notably high at 86%. In contrast, June offers warmer conditions, with temperatures ranging from a minimum of 3°C (38°F) to a maximum of 30°C (86°F), averaging 16°C (61°F). Although June also sees some precipitation, it totals 86 mm (3.4 in) across 12 days and comes with lower humidity levels at 71%. For more details, you can check Oslo weather in June.

September weather is notably cooler compared to July, with average temperatures ranging from a minimum of 1°C (35°F) to a maximum of 25°C (77°F), while July enjoys milder temperatures between 5°C (41°F) and 32°C (90°F). Both months experience similar levels of precipitation, with September receiving slightly more at 106 mm (4.2 in) over 13 days, compared to July's 103 mm (4.1 in) over 11 days. Additionally, September has a higher humidity level at 86%, making it feel more damp than the 72% humidity typically seen in July. For a closer look at July's weather specifics, you can visit Oslo weather in July.

In August, the weather in Oslo tends to be warmer, with minimum temperatures around 5°C (42°F) and average temperatures of 15°C (60°F), reaching a maximum of 28°C (83°F). In contrast, September sees a drop in temperatures, where the minimum is 1°C (35°F) and the average is 12°C (53°F), with a maximum of 25°C (77°F). Precipitation levels remain similar in both months, with August receiving 100 mm (3.9 in) and September slightly higher at 106 mm (4.2 in), with 13 rainy days in both months. Additionally, September features a higher humidity level of 86%, compared to 77% in August. For more details about August weather, you can check Oslo weather in August.

In September, the weather is relatively mild with temperatures ranging from a chilly 1°C (35°F) at night to a warm 25°C (77°F) during the day, averaging around 12°C (53°F). The month sees a total precipitation of 106 mm (4.2 in) over approximately 13 rainy days, accompanied by a high humidity level of 86%.

As we move into October, the temperatures drop further, with nighttime lows dipping to -4°C (25°F) and daytime highs peaking at 17°C (63°F), bringing the average down to 7°C (44°F). Additionally, October experiences an uptick in precipitation, totaling 130 mm (5.1 in) over 14 days, and humidity increases to 92%. For a detailed outlook on the weather in Oslo during this month, visit Oslo weather in October.

In September, temperatures in Oslo range from a minimum of 1°C (35°F) to a maximum of 25°C (77°F), with an average of 12°C (53°F), making it a mild transitional month. The month receives around 106 mm (4.2 in) of precipitation over approximately 13 days, with humidity levels at 86%.

In contrast, November sees a significant drop in temperatures, with a minimum of -9°C (15°F) and a maximum of 14°C (57°F), resulting in an average temperature of just 2°C (36°F). Precipitation remains similar, at 107 mm (4.2 in), but occurs over slightly fewer days (12 days), while humidity rises to 93%. For more details on the weather in November, you can check Oslo weather in November.

September and December present stark contrasts in weather. In September, temperatures range from a mild 1°C (35°F) to a pleasant max of 25°C (77°F), with an average of 12°C (53°F). The month experiences about 106 mm (4.2 in) of precipitation over 13 days and boasts a humidity level of 86%. In contrast, December brings much colder conditions, with temperatures plummeting to a minimum of -16°C (3°F) and reaching a maximum of only 7°C (45°F), averaging -2°C (28°F). Though precipitation remains similar at 107 mm (4.2 in), it is spread over 16 days, and humidity rises to 93%. For more detailed information, check Oslo weather in December.

Compare Oslo's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Oslo

As summer gracefully transitions into autumn, September in Oslo presents a unique blend of lingering warmth and the first whispers of cooler temperatures. While the days can still reach pleasant highs, the average temperature showcases a significant drop, inviting a crispness in the air. Rain becomes more frequent, with over a week of the month experiencing precipitation, contributing to the lush, vibrant scenery that Oslo is known for. The higher humidity adds to the refreshing feel, making this month a beautiful time to explore the city as it shifts into fall. For more insights on how Oslo’s weather evolves throughout the year, check out Oslo Climate.