September Weather in Sonderborg, Denmark

Last updated: October 30, 2025

September in Sonderborg, Denmark, showcases a mild climate characterized by maximum temperatures reaching 27°C (80°F) and an average of 15°C (58°F). While the month can experience cooler moments with minimum temperatures dropping to 5°C (42°F), the air remains humid, with levels hovering around 84%. Rain is frequent, with 64 mm (2.5 in) of precipitation spread over 11 days, encouraging the lush greenery that September is known for in this picturesque coastal town. This blend of warmth and moisture makes it a captivating time to explore Sonderborg’s serene landscapes and cultural offerings.

September Temperature in Sonderborg

In September, Sonderborg, Denmark experiences a remarkable transition into autumn, marked by increasingly mild conditions. With average temperatures hovering around 15°C (58°F), the month begins to cool from the summer heat, though highs can still reach 27°C (80°F), making for pleasantly warm days. The shift is evident as nighttime temperatures drop to a minimum of 5°C (42°F), hinting at the chillier months ahead. This moderate climate is ideal for outdoor activities, as the remnants of summer linger, providing a unique opportunity to enjoy the last warm days before the crispness of fall sets in. As September progresses, it's clear that Sonderborg is on the cusp of transitioning into autumn, inviting residents and visitors alike to savor the beauty of these early fall days.

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

The chart illustrates September temperature patterns in Sonderborg, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sonderborg, September typically has an average temperature of 15°C (58°F), with highs reaching up to 27°C (80°F) and lows dropping to around 5°C (42°F).
JanFebMarAprMayJunJulAugSepOctNovDec383740465362646458524540
Data source: Temperature data for Sonderborg 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 Sonderborg

In September, Sonderborg experiences a noticeable shift in precipitation patterns, with 64 mm (2.5 in) of rain falling over 11 days. This marks a return to wetter conditions as the summer months give way to autumn, with September's rainfall being slightly lower than August's peak of 77 mm (3.0 in) but still significant. The total rainfall reflects the transitional nature of the season, where lush growth from the warmer months meets the impending chill of autumn. As the days shorten and temperatures begin to drop, residents can expect regular drizzles and the occasional downpour, setting the stage for the wetter October that follows, historically recording an even higher total of 82 mm (3.2 in).

September Precipitation Trends in Sonderborg

The chart displays monthly precipitation patterns in Sonderborg, 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 Sonderborg, September typically receives around 64 mm (2.5 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec485763386361677765824960
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Sonderborg

In Sonderborg, Denmark, September ushers in a noticeable change in humidity, averaging around 84%. Following the summer months, where humidity hovered between 75% and 77%, this slight increase signals the transition into autumn. It’s a time when the air begins to feel crisper, hinting at the cozy warmth of fall while still retaining some of summer's residual moisture. As the year progresses, humidity trends show that after September, levels will rise again, peaking to 87% in October and November, as the colder months approach, enveloping Sonderborg in a familiar, damp embrace. The ebb and flow of humidity throughout the year not only shapes the local climate but also influences the lush, vibrant landscape that defines this charming Danish town.

September Average Humidity in Sonderborg

This chart illustrates the average monthly humidity levels in Sonderborg, 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 Sonderborg is approximately 84%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%88%87%84%79%75%76%77%84%87%88%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Sonderborg

As September arrives in Sonderborg, Denmark, the UV Index experiences a notable shift, settling at 5, categorized as moderate. This marks a decrease from the summer months, where the index peaked at 7 in both June and July, indicating high sun intensity. With a burn time of 30 minutes, it's essential for locals and visitors alike to stay mindful of sun protection during outdoor activities. The trend shows a gradual transition from the intense rays of summer back to more moderate exposure levels, paving the way for autumn while reminding everyone to keep their skin safe. For more detailed information on UV levels throughout the year, visit Sonderborg UV Index.

Maximum UV Index Levels in Sonderborg for September

The chart shows the monthly maximum UV Index (UVI) for Sonderborg 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 Sonderborg typically reaches 5, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec123567765321
Data source: Sonderborg 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 Sonderborg

September in Sonderborg, Denmark, truly captures the essence of transitioning seasons, basking in 314 hours of sunlight. As summer bids farewell, the days remain luminous, offering a delightful contrast to the shorter hours that follow in October. This month reflects a gradual decline from the sun-drenched heights of July and June, which boast an impressive 440 and 430 hours respectively. While the sun's embrace ebbs slightly, September still shines brighter than five of its preceding months, establishing it as a key period of lingering warmth and vibrant outdoor activities. As autumn begins to unfurl its colors, Sonderborg enjoys a perfect balance of sunshine, making September a cherished time to relish the last glimmers of summer.

Monthly Sunshine Duration in Sonderborg: September Highlighted

The September sunshine duration represents the total number of hours Sonderborg 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.
JanFebMarAprMayJunJulAugSepOctNovDec101h180h251h362h414h430h440h401h314h250h154h116h
Data source: Sonderborg September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Sonderborg During September

In Sonderborg, Denmark, the chances of enjoying sunny weather in September hover around 28%, reflecting a subtle decline from the summer's warmer months. This marks a transitional period where the lingering warmth of August, which enjoys a 37% chance of sun, begins to fade. Interestingly, this gradual dip in sunshine is part of a broader trend as the year progresses; the likelihood of sunny days typically peaks in the spring and summer months, with a steady decrease into the chillier fall and winter. While September may not boast the highest probability for sunshine, it still offers a fair chance to relish those late summer vibes before the colder months set in.

Percentage of Sunny Days in September in Sonderborg

The chart illustrates the percentage of sunny days in Sonderborg 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 Sonderborg experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec19%25%37%50%23%34%30%37%28%26%17%22%
Data source: Sonderborg September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Sonderborg in September

In Sonderborg, Denmark, the daylight duration experiences a captivating ebb and flow throughout the year, reflecting the changing seasons. As summer approaches, daylight peaks in June with an impressive 17 hours of sun, offering golden hours for outdoor activities. By September, however, this luminous bounty begins to wane, with daylight reducing to 12 hours. This transition marks the onset of autumn, as the days steadily shorten, leading into October’s 10 hours of daylight. The gradual decrease from August's 14 hours is a gentle reminder of nature's cyclical rhythm, fostering a sense of anticipation for the cozy months ahead. As we move towards winter, the return to 7 hours of daylight in December underscores the stark contrast of the seasons, inviting a reflective pause amidst the twilight.

Average Daylight Hours in Sonderborg for September

The chart illustrates the variation in daylight duration in Sonderborg throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec7h 51m9h 41m11h 53m14h 9m16h 10m17h 15m16h 40m14h 50m12h 39m10h 25m8h 22m7h 15m
Data source: Sonderborg daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Sonderborg

As September unfolds in Sonderborg, Denmark, the wind whispers a gentle refrain, averaging 4.0 m/s (9 mph), slightly lower than the summer months. This subtle shift indicates the transition into autumn, where the breezes become softer, inviting a tranquil ambiance. Throughout the year, wind speeds show a dynamic rhythm; January's brisk gusts peak at 4.7 m/s and maintain a steady presence until autumn, before a brief uptick in October brings the wind back to a lively 5.1 m/s (11 mph). Overall, the data portrays a graceful ebb and flow, keeping Sonderborg's coastal charm alive through each seasonal change.

Average September Wind Speed in Sonderborg

The chart displays monthly wind speed patterns in Sonderborg, 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.
JanFebMarAprMayJunJulAugSepOctNovDec4.75.14.64.74.43.64.14.64.0 m/s5.14.64.9
Data source: Sonderborg September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Sonderborg Compares to Other Months

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

September and January present contrasting weather patterns, reflecting the shift from late summer to mid-winter. In September, temperatures range from a minimum of 5°C (42°F) to a maximum of 27°C (80°F), showcasing a pleasant average of 15°C (58°F). The month experiences an average precipitation of 64 mm (2.5 in) over approximately 11 days, with humidity hovering around 84%. In stark contrast, January brings much colder temperatures, with a minimum of -9°C (15°F) and a maximum of 11°C (53°F), averaging just 3°C (38°F). While precipitation decreases slightly to 48 mm (1.9 in) over the same number of days, humidity rises to a chilly 89%. For more detailed insights on the winter weather, check out Sonderborg weather in January.

September and February present quite contrasting weather conditions. In September, temperatures range from a minimum of 5°C (42°F) to a pleasant average of 15°C (58°F), peaking at a warm 27°C (80°F). This month experiences a total precipitation of 64 mm (2.5 in) over approximately 11 days, accompanied by high humidity levels of 84%. Conversely, February is much colder, with temperatures dropping to a minimum of -14°C (7°F) and an average of only 3°C (38°F), rising to a maximum of 14°C (58°F). There is slightly less rainfall in February, totaling 57 mm (2.3 in) across 12 days and with humidity at a higher level of 88%. For a detailed look at February weather specifics, you can check Sonderborg weather in February.

September and March present contrasting weather patterns. In September, temperatures range from a mild 5°C (42°F) at night to a pleasant average of 15°C (58°F) during the day, peaking at 27°C (80°F). This month sees around 64 mm (2.5 in) of precipitation over approximately 11 days, with humidity levels at a comfortable 84%.

In contrast, March is much cooler, with temperatures dropping to a minimum of -8°C (19°F) and an average of just 4°C (40°F). The maximum temperature reaches 16°C (60°F), but overall, it feels much colder. Despite having a similar amount of precipitation at 63 mm (2.5 in) over 12 days, March is accompanied by higher humidity at 87%. For more detailed information about March weather, you can visit Sonderborg weather in March.

When comparing the weather in September and April, we notice several distinct differences. September generally enjoys milder temperatures, ranging from a minimum of 5°C (42°F) to a maximum of 27°C (80°F), with an average of 15°C (58°F). In contrast, April experiences cooler conditions, with temperatures dipping as low as -2°C (29°F) and peaking at 23°C (74°F), averaging just 8°C (46°F).

Precipitation levels also vary, with September receiving 64 mm (2.5 in) over approximately 11 days, while April sees less rain at 37 mm (1.5 in) across 8 days. Despite these differences, both months share the same high humidity level of 84%. For more detailed insights into April's weather, you can visit Sonderborg weather in April.

In comparing the weather between September and May, both months exhibit relatively mild conditions but differ in temperature and humidity. September typically experiences higher temperatures, averaging around 15°C (58°F), with a maximum reaching 27°C (80°F), whereas May averages at 12°C (54°F) and peaks at 25°C (77°F). Interestingly, both months receive similar amounts of precipitation, around 64 mm (2.5 in) over approximately 11 days. However, September tends to be slightly more humid at 84%, compared to May's 79%. For more detailed information, you can check Sonderborg weather in May.

In comparing the weather of September and June, both months present mild temperatures but with notable differences. September typically sees a minimum temperature of 5°C (42°F) and an average of 15°C (58°F), while June starts slightly warmer, with a minimum of 7°C (46°F) and an average of 17°C (62°F). The maximum temperatures are comparable, with September reaching up to 27°C (80°F) and June peaking at 28°C (83°F). Precipitation levels are similar in both months, around 61-64 mm (2.4-2.5 in), but September experiences slightly higher humidity at 84% compared to June's 75%. For a more detailed look at the weather in June, you can visit Sonderborg weather in June.

In comparing the weather of September and July, September experiences cooler temperatures, with a minimum of 5°C (42°F) and an average of 15°C (58°F), while July enjoys warmer conditions, hitting a minimum of 9°C (48°F) and an average of 18°C (64°F). The maximum temperature in July peaks at 31°C (87°F), contrasting with September’s highest of 27°C (80°F). Precipitation levels are relatively similar, with September receiving 64 mm (2.5 in) over 11 days compared to July’s 67 mm (2.6 in) over 12 days. Additionally, September has higher humidity at 84%, compared to July’s 76%. For more information about July weather in Sonderborg, you can check Sonderborg weather in July.

In comparing the weather between September and August, September tends to be cooler with average temperatures ranging from a minimum of 5°C (42°F) to a maximum of 27°C (80°F), while August offers warmer conditions, with average temperatures from a minimum of 8°C (46°F) up to 32°C (89°F). August also experiences slightly more rainfall, totaling 77 mm (3.0 in) over 13 days, compared to September’s 64 mm (2.5 in) over 11 days. Additionally, September has higher humidity levels at 84%, in contrast to August's 77%. For a detailed comparison of the August weather, you can refer to Sonderborg weather in August.

Comparing the weather between September and October reveals a noticeable shift in temperature and precipitation patterns. In September, temperatures range from a minimum of 5°C (42°F) to a maximum of 27°C (80°F), with an average of 15°C (58°F) and a total precipitation of 64 mm (2.5 in) over 11 days. As we move into October, the temperatures dip further, with a minimum of 1°C (34°F) and an average of 11°C (52°F), peaking at 23°C (74°F). The month also sees an increase in rainfall, accumulating 82 mm (3.2 in) across 14 days. Additionally, humidity levels rise slightly from 84% in September to 87% in October, indicating a trend towards cooler, wetter conditions. For more details on October weather, you can check this link: Sonderborg weather in October.

September and November offer contrasting weather patterns. In September, temperatures range from a mild 5°C (42°F) at night to a comfortable 27°C (80°F) during the day, with an average of 15°C (58°F). This month also experiences relatively higher precipitation at 64 mm (2.5 in) over 11 days and a humidity level of 84%. In contrast, November sees a significant drop in average temperature, with lows dipping to 0°C (32°F) and a maximum of 17°C (63°F), averaging just 7°C (45°F). Precipitation decreases slightly to 49 mm (1.9 in) across the same number of rainy days, though humidity rises to 88%. For a more detailed look at November weather specifics, visit Sonderborg weather in November.

September and December exhibit stark contrasts in weather conditions. In September, temperatures range from a minimum of 5°C (42°F) to a maximum of 27°C (80°F), providing an average of 15°C (58°F). The month experiences moderate precipitation of 64 mm (2.5 in) over 11 days, with humidity levels at 84%. In sharp contrast, December sees much colder temperatures, with a minimum of -14°C (8°F) and a maximum of 11°C (52°F), resulting in an average of only 4°C (40°F). Though precipitation slightly decreases to 60 mm (2.4 in) over 13 days, humidity rises to 87%, contributing to a much chillier atmosphere. For more detailed information about weather conditions during December, you can visit Sonderborg weather in December.

Compare Sonderborg's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Sonderborg

As summer fades, September in Sonderborg offers a unique blend of mild warmth and refreshing coolness, setting it apart from the sweltering highs of summer months. With an average temperature around 15°C, the days are comfortably warm while the nights can dip to a crisp 5°C, inviting cozy layers for evening strolls. Although 11 days may greet you with rainfall, the humidity remains high at 84%, creating a mild, invigorating atmosphere perfect for enjoying the scenic charm of this coastal town. For a comprehensive overview of what to expect throughout the year, check out Sonderborg Climate.