September Weather in Sarpsborg, Norway

Last updated: August 27, 2025

In September, Sarpsborg, Norway experiences a mild transition into autumn, with temperatures ranging from a maximum of 24°C (76°F) to a minimum of 0°C (33°F), averaging around 13°C (56°F). This month is characterized by a notable 101 mm (4.0 in) of precipitation spread over 11 days, leading to a humid atmosphere with levels reaching 86%. As the vibrant hues of fall emerge, September offers a unique blend of early autumn warmth and refreshing, rainy days.

September Temperature in Sarpsborg

In September, Sarpsborg, Norway begins to transition from the warmth of summer to the cooler embrace of autumn. With temperatures ranging from a mild 0°C (33°F) at night to a pleasant 24°C (76°F) during the day, the month offers a comfortable average of 13°C (56°F). This gentle decline from the peak summer heat is marked by a notable decrease in both minimum and maximum temperatures compared to the preceding months, creating an inviting environment for outdoor activities and enjoying the vibrant fall foliage. As the leaves start to change, September stands as a bridge between seasons, offering a refreshing reprieve before the chill of winter sets in.

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

The chart illustrates September temperature patterns in Sarpsborg, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sarpsborg, 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).
JanFebMarAprMayJunJulAugSepOctNovDec343337445363656256484034
Data source: Temperature data for Sarpsborg 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 Sarpsborg

In September, Sarpsborg experiences a notable surge in precipitation, with an average of 101 mm (4.0 in), marking it as one of the wettest months in the year. This increase in rainfall, spread over 11 days, reflects a significant transition as summer fades and autumn takes hold. Following the relatively drier months of late spring and early summer, September's generous downpours set the stage for the wetter autumn months ahead, culminating in October's even heftier average of 117 mm (4.6 in). This trend highlights not just the arrival of cooler weather, but also the importance of September as a pivotal month for replenishing the local ecosystem before winter's approach.

September Precipitation Trends in Sarpsborg

The chart displays monthly precipitation patterns in Sarpsborg, 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 Sarpsborg, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec54605931687488861011178887
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Sarpsborg

As autumn approaches in Sarpsborg, Norway, September experiences a notable increase in humidity, with levels reaching 86%—a marked rise from the drier summer months. After a peak in August at 77%, this uptick signals a transition towards the wetter months ahead. The humidity gradually climbs again, reminiscent of the earlier winter months, where January and February boast figures above 90%. This trend illustrates a cyclical pattern in Sarpsborg's climate, where summer's warmth gives way to the crisp, moisture-laden air of fall, setting the stage for the damp chill of winter that lies just around the corner.

September Average Humidity in Sarpsborg

This chart illustrates the average monthly humidity levels in Sarpsborg, 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 Sarpsborg 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 Sarpsborg

As September rolls into Sarpsborg, Norway, the UV Index remains at a moderate 4, indicating a slight decrease from the summer months. This trend reflects the gradual transition from the intense high UV levels of June and July, which saw a peak UV Index of 7. With a burn time of around 30 minutes, sun exposure is still significant, but precautions are advised, especially during midday hours. The shift toward lower UV levels continues into October, where the Index drops to 2, aligning with the seasonal change. For a detailed month-by-month breakdown, visit Sarpsborg UV Index.

Maximum UV Index Levels in Sarpsborg for September

The chart shows the monthly maximum UV Index (UVI) for Sarpsborg 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 Sarpsborg typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec113457754211
Data source: Sarpsborg 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 Sarpsborg

As summer fades into autumn, September in Sarpsborg, Norway, continues to bask in a generous 290 hours of sunshine. This marks a notable decline from the sun-drenched days of July and August, which boasted over 475 and 409 hours, respectively. However, September still shines brighter than several upcoming months, particularly October, which typically sees just 236 hours. This gentle transition signals the end of a vibrant season, while hinting at the chilly, darker months ahead. The gradual decrease in daylight reflects the region's shifting rhythms, as nature prepares for its winter slumber, yet September offers a lovely balance of warmth and light, perfect for those looking to savor the last hints of summer.

Monthly Sunshine Duration in Sarpsborg: September Highlighted

The September sunshine duration represents the total number of hours Sarpsborg 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.
JanFebMarAprMayJunJulAugSepOctNovDec91h180h288h373h429h464h475h409h290h236h137h99h
Data source: Sarpsborg September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Sarpsborg During September

In September, Sarpsborg, Norway, experiences a notable decline in sunny weather, with only a 27% chance of sunshine. This marks a significant drop from the 55% in April and represents the lowest likelihood of sun recorded throughout the year. As summer transitions into autumn, the region’s weather patterns shift, leading to cloudier skies and increased precipitation. This trend highlights a general pattern, where the sunny days become less frequent as the year progresses, with autumn settling in, paving the way for cooler and darker days ahead.

Percentage of Sunny Days in September in Sarpsborg

The chart illustrates the percentage of sunny days in Sarpsborg 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 Sarpsborg experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec35%42%44%55%31%42%45%41%27%31%23%30%
Data source: Sarpsborg September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Sarpsborg in September

As summer transitions into autumn, September in Sarpsborg, Norway, offers a gradual decrease in daylight, with the sun casting its glow for approximately 12 hours each day. This is a slight dip from the vibrant 15 hours enjoyed in August, marking the shift towards shorter days as the year approaches its end. Following the peak daylight of 18 hours in June, the gradual decline continues, reflecting the natural rhythm of the seasons. By the time October rolls in, residents will experience just 10 hours of daylight, underscoring the enchanting yet fleeting nature of summer's brightness as autumn firmly takes hold.

Average Daylight Hours in Sarpsborg for September

The chart illustrates the variation in daylight duration in Sarpsborg throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec6h 58m9h 14m11h 52m14h 33m17h 1m18h 26m17h 40m15h 23m12h 46m10h 6m7h 38m6h 12m
Data source: Sarpsborg daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Sarpsborg

As September rolls into Sarpsborg, a distinct shift in the seasonal breeze can be felt, with an average wind speed of 3.5 m/s (8 mph), slightly more invigorating than the calmer summer months. This gentle increase from the summer's lull, seen in July and August with averages of 3.1 m/s (7 mph) and 3.3 m/s (7 mph) respectively, signals the approach of autumn. Interestingly, this trend continues as the winds pick up pace into October, where they soar to 4.7 m/s (11 mph), hinting at a more dynamic and refreshing atmosphere ahead. Overall, September serves as a transitional bridge, offering a refreshing breath of wind that hints at the energetic shifts the fall season will bring.

Average September Wind Speed in Sarpsborg

The chart displays monthly wind speed patterns in Sarpsborg, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3.73.93.93.83.33.43.13.33.5 m/s4.73.93.5
Data source: Sarpsborg September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Sarpsborg Compares to Other Months

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

September and January present contrasting weather conditions. In September, temperatures range from a chilly 0°C (33°F) at night to a pleasant average of 13°C (56°F) during the day, peaking at 24°C (76°F). This month experiences relatively high humidity at 86%, along with 101 mm (4.0 in) of precipitation spread across 11 days. Conversely, January is much colder, with temperatures dipping as low as -15°C (5°F) and averaging just 1°C (34°F); the maximum reaches only 11°C (53°F). Despite the cold, January sees less rain, totaling 54 mm (2.1 in) over 9 days, but with even higher humidity at 94%. For a more detailed look at January weather, you can visit Sarpsborg weather in January.

September and February present contrasting weather patterns. In September, temperatures range significantly from a chilly 0°C (33°F) at night to a pleasant 24°C (76°F) during the day, with an average of 13°C (56°F). The month sees around 101 mm (4.0 in) of precipitation over approximately 11 days, contributing to a relatively high humidity of 86%. In stark contrast, February experiences much colder conditions, with temperatures dipping as low as -16°C (4°F) and peaking at only 12°C (54°F), averaging around 0°C (33°F). Precipitation is less frequent, with 59 mm (2.3 in) over about 10 days and an even higher humidity level of 92%. For more details, you can explore Sarpsborg weather in February.

In September, Sarpsborg experiences milder temperatures, with an average of 13°C (56°F) and a maximum of 24°C (76°F), compared to the cooler March, where the average temperature is only 3°C (37°F) and can dip to a minimum of -13°C (9°F). Rainfall is more frequent in September, totaling 101 mm (4.0 in) over 11 days, while March sees less precipitation at 59 mm (2.3 in) across 9 days. Interestingly, the humidity levels remain quite high in both months, with September at 86% and March slightly higher at 89%. For more detailed insights into the weather during March, you can explore Sarpsborg weather in March.

When comparing the weather in September and April, a few key differences stand out. September generally enjoys milder temperatures, with an average of 13°C (56°F) and highs reaching up to 24°C (76°F), while April has a cooler average of 7°C (45°F), peaking at 22°C (71°F). Furthermore, September experiences notably more precipitation, totaling 101 mm (4.0 in) over 11 days, in contrast to April's 31 mm (1.2 in) across just 6 days. Humidity levels are also quite high in both months, with September at 86% and April slightly lower at 82%. For a detailed look at April's weather, check out Sarpsborg weather in April.

In September, the weather offers a mild average temperature of 13°C (56°F), with daily highs reaching up to 24°C (76°F) and lows dipping to 0°C (33°F). The month experiences a higher humidity level of 86% and more precipitation, totaling 101 mm (4.0 in) over approximately 11 days. In contrast, May welcomes warmer temperatures, with an average of 12°C (53°F), and maximums peaking at 31°C (88°F). It has less precipitation, amounting to 68 mm (2.7 in) over the same number of days, and a drier atmosphere, indicated by the lower humidity level of 73%. For more details, you can explore Sarpsborg weather in May.

September and June offer contrasting weather experiences. In September, temperatures range from a chilly 0°C (33°F) at night to a mild 24°C (76°F) during the day, with an average temperature of 13°C (56°F). The month is quite wet, receiving 101 mm (4.0 in) of precipitation over 11 days and boasting a high humidity of 86%. In comparison, June features warmer temperatures, with nighttime lows of 5°C (42°F) and daytime highs reaching 30°C (87°F), averaging around 17°C (63°F). This month sees less precipitation at 74 mm (2.9 in) spread over 12 days, and the humidity is notably lower at 71%. For a detailed look at June's weather patterns, check out Sarpsborg weather in June.

In comparing the weather of September and July, a noticeable shift in temperature and humidity is evident. September features a minimum temperature of 0°C (33°F) and an average of 13°C (56°F), creating a cooler atmosphere as the summer fades. In contrast, July boasts milder conditions with a minimum of 8°C (47°F) and an average temperature of 18°C (65°F). Additionally, September experiences higher humidity at 86%, compared to July's 72%. Despite having similar precipitation days—11 in each month—September receives slightly more rain, totaling 101 mm (4.0 in), while July has 88 mm (3.5 in). For more details on July weather patterns, visit Sarpsborg weather in July.

In September, the weather in Sarpsborg cools down compared to August, with minimum temperatures dropping to around 0°C (33°F) and average temperatures resting at 13°C (56°F). In contrast, August enjoys milder conditions, with minimum temperatures around 6°C (43°F) and an average of 17°C (62°F). While September experiences an increase in rainfall, with 101 mm (4.0 in) over 11 days, August is slightly drier, recording 86 mm (3.4 in) across 14 days. Additionally, September's humidity is higher at 86%, compared to August's 77%. For a closer look at August weather specifics, check out Sarpsborg weather in August.

September and October show notable differences in weather patterns. In September, temperatures range from a minimum of 0°C (33°F) to a maximum of 24°C (76°F), with an average of 13°C (56°F). The month experiences 101 mm (4.0 in) of precipitation over 11 days, with humidity levels at 86%. In contrast, October brings chillier conditions, with temperatures dropping to a minimum of -4°C (26°F) and an average of 9°C (48°F), reaching a maximum of 18°C (64°F). The precipitation increases slightly to 117 mm (4.6 in), spread over 14 days, and humidity rises to 92%. For more detailed insights on the October weather, you can visit Sarpsborg weather in October.

In September, temperatures in Sarpsborg range from a chilly 0°C (33°F) at night to a warm 24°C (76°F) during the day, with an average of 13°C (56°F). The month sees significant precipitation with about 101 mm (4.0 in) spread over 11 days and a relatively high humidity of 86%.

In contrast, November brings cooler weather, with temperatures dropping to a minimum of -9°C (16°F) and averaging only 4°C (40°F), while the maximum temperature reaches up to 15°C (60°F). The precipitation is slightly lower at 88 mm (3.5 in), but it occurs over a longer period of 13 days, contributing to a higher humidity level of 93%. The transition from September to November marks a notable shift towards winter conditions, with colder temperatures and increased moisture. For more detailed information, you can visit Sarpsborg weather in November.

September and December offer stark contrasts in weather patterns. In September, temperatures range from a minimum of 0°C (33°F) to a comfortable maximum of 24°C (76°F), with an average of 13°C (56°F). While it experiences some rainfall, totaling 101 mm (4.0 in) over 11 days, the humidity sits at a moderate 86%. In contrast, December brings a chillier climate, where temperatures can plummet to a minimum of -13°C (10°F) and reach a maximum of only 10°C (51°F), averaging just 1°C (34°F). Despite slightly lower precipitation at 87 mm (3.4 in), it is spread over more days, with rain or snow occurring on 15 days and humidity rising to 93%. For more detailed information, check out Sarpsborg weather in December.

Compare Sarpsborg's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Sarpsborg

September in Sarpsborg marks a transition from the warmth of summer to the crispness of autumn. With average temperatures hovering around a comfortable 13°C, it provides a refreshing escape from the heat, while occasional peaks of warmth remind us of the season just passed. However, as the month unfolds, the increased humidity and precipitation, featuring around 11 rainy days, signal a shift towards wetter weather compared to the drier summer months. This combination of factors results in a landscape rich with vibrant autumn colors, making September a unique and visually stunning time to explore. For a more detailed overview of what to expect throughout the year, visit Sarpsborg Climate.