September Weather in Rheinfelden, Switzerland

Last updated: August 27, 2025

September in Rheinfelden, Switzerland, offers a captivating blend of warm and cool weather, with maximum temperatures reaching up to 30°C (86°F) and an average of 16°C (61°F). As summer transitions to autumn, residents can expect temperatures to dip as low as 2°C (36°F). This month embraces a notable precipitation total of 69 mm (2.7 in) over 12 days, contributing to the lush landscape. With humidity levels at a comfortable 83%, September presents a unique opportunity for outdoor activities, enveloped in Switzerland's picturesque scenery.

September Temperature in Rheinfelden

As September rolls into Rheinfelden, Switzerland, the summer's warmth begins to wane, but not without leaving its mark. With minimum temperatures settling around 2°C (36°F) and averages reaching a comfortable 16°C (61°F), the month invites outdoor enthusiasts to bask in the mild weather. Daytime highs can still touch an inviting 30°C (86°F), allowing for lingering moments in the sun amidst the beautiful fall foliage. The transition from the blazing heat of summer to the cooler embrace of autumn is palpable, as September serves as a perfect bridge, offering pleasant days and cooler nights that hint at the changing seasons ahead.

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

The chart illustrates September temperature patterns in Rheinfelden, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Rheinfelden, 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).
JanFebMarAprMayJunJulAugSepOctNovDec353943505766686860514138
Data source: Temperature data for Rheinfelden 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 Rheinfelden

In September, Rheinfelden experiences a moderate decline in precipitation, receiving 69 mm (2.7 in) over about 12 days. This marks a noticeable dip from the summer months, which typically see higher rainfall, particularly July and August, where averages soar above 120 mm. However, this month's total still reflects the region's overall trend of consistent rainfall, following a relatively wet summer and leading into the autumn months. As the year progresses, September's weather serves as a bridging period, signaling a transition towards the wetter autumn months characterized by increasing precipitation averages in October and December.

September Precipitation Trends in Rheinfelden

The chart displays monthly precipitation patterns in Rheinfelden, 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 Rheinfelden, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec89758759126120122115699073124
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Rheinfelden

In September, Rheinfelden experiences a notable shift in humidity, maintaining a comfortable level of 83%. This marks a slight increase from the drier summer months of July and August, which hovered around 83% and 80%, respectively. As the year transitions into autumn, the humidity edges toward the higher levels seen in October, where it jumps to 90%. Overall, September serves as a bridge between the warm summer and the cooler, more humid fall, setting the stage for the end of the year when humidity consistently climbs back up to the higher percentages observed in winter. This gradual increase throughout the months illustrates Rheinfelden's characteristic trend of rising humidity as the seasons change.

September Average Humidity in Rheinfelden

This chart illustrates the average monthly humidity levels in Rheinfelden, 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 Rheinfelden is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec92%89%87%84%80%82%83%80%83%90%89%90%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Rheinfelden

As summer transitions to autumn in Rheinfelden, Switzerland, September sees the UV Index moderate at 6, indicating a high exposure category. This marks a noticeable decline from the intense levels experienced in the peak summer months of June and July, which reached a UV Index of 9. With a burn time of 25 minutes, it's crucial to stay vigilant about sun safety as the days grow shorter but still pack a punch. The trends illustrate the importance of adjusting your sun protection measures as the seasons change, ensuring you're well-prepared for varying UV levels. For more detailed information, visit Rheinfelden UV Index.

Maximum UV Index Levels in Rheinfelden for September

The chart shows the monthly maximum UV Index (UVI) for Rheinfelden 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 Rheinfelden typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec235689986421
Data source: Rheinfelden 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 Rheinfelden

As summer gracefully transitions into autumn, September in Rheinfelden, Switzerland, offers a delightful decline in sunshine hours, recording an impressive 323 hours of sunlight. This month serves as a bridge between the sun-drenched days of July and August, which boast the highest sunshine hours at 413 and 381 respectively, and the cooler, dimmer months that follow. The trend shows a radiant journey from the depths of winter, where January barely scrapes 136 hours, to the warmth of late summer, peaking in the sunniest months. September, with its golden light, provides a lovely backdrop for outdoor activities, inviting locals and visitors alike to savor the last remnants of warmth before the days shorten further into the fall.

Monthly Sunshine Duration in Rheinfelden: September Highlighted

The September sunshine duration represents the total number of hours Rheinfelden 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.
JanFebMarAprMayJunJulAugSepOctNovDec136h211h283h353h361h389h413h381h323h265h192h156h
Data source: Rheinfelden September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Rheinfelden During September

As September rolls in, Rheinfelden, Switzerland, boasts a 43% chance of sunny weather, making it one of the brighter months of the year. This figure reflects a notable uptick from the summer months of June and July, which linger around the low 30s in terms of sunshine probability. Following the brightening trend from late spring, where April peaks at 51%, September provides a moderate balance of sunshine, hinting at a pleasant transition into autumn. While the days might not be as consistently sunny as earlier in the summer, there's a renewed optimism for enjoying the lingering warmth of the season. Thus, if you're planning a visit, September offers a cheerful window of opportunity for outdoor adventures in this picturesque Swiss region.

Percentage of Sunny Days in September in Rheinfelden

The chart illustrates the percentage of sunny days in Rheinfelden 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 Rheinfelden experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec17%38%47%51%33%32%38%40%43%37%23%26%
Data source: Rheinfelden September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Rheinfelden in September

As September unfolds in Rheinfelden, Switzerland, daylight lingers for about 12 hours a day, marking a graceful transition from the sun-soaked months of summer. Following the peak of 15 hours of daylight experienced in May through July, the duration begins to taper, signaling the impending arrival of autumn. The gradual decline from the lively 14 hours in August to September’s more mellow offering reflects nature’s rhythm, as the days shorten and the nights lengthen. Embracing this shift fosters a unique charm in Rheinfelden, where the golden hues of fall begin to paint the landscape, inviting residents and visitors alike to savor the fading warmth of the sun while preparing for the cozy embrace of the colder months ahead.

Average Daylight Hours in Rheinfelden for September

The chart illustrates the variation in daylight duration in Rheinfelden throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec8h 54m10h 15m11h 56m13h 39m15h 8m15h 53m15h 29m14h 10m12h 30m10h 48m9h 17m8h 29m
Data source: Rheinfelden daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Rheinfelden

In Rheinfelden, Switzerland, the gentle September wind ushers in a noticeable shift as summer begins to wane. With an average wind speed of only 1.6 m/s (4 mph), September marks one of the calmest months of the year, reflecting a steady decline from the more breezy late spring. As the winds taper off from the higher 2.7 m/s (6 mph) in May and the consistent breezes of early summer, the light air of September offers a tranquil backdrop for the picturesque town. This trend of diminishing wind speeds continues into the fall, with October and November hovering around 1.9 m/s (4 mph) and 2.0 m/s (4 mph), respectively. Such serene conditions are perfect for savoring the stunning autumn scenery without the distraction of blustery winds, allowing one to fully appreciate the beauty of Rheinfelden’s changing landscape.

Average September Wind Speed in Rheinfelden

The chart displays monthly wind speed patterns in Rheinfelden, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.52.32.32.32.71.71.91.91.6 m/s1.92.02.5
Data source: Rheinfelden September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Rheinfelden Compares to Other Months

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

In September, the weather is quite mild, with temperatures ranging from a minimum of 2°C (36°F) to a maximum of 30°C (86°F). The average temperature is a comfortable 16°C (61°F), accompanied by a relatively low precipitation of 69 mm (2.7 in) over 12 days, and a humidity level of 83%. In stark contrast, January brings much colder conditions, starting from a frigid minimum of -13°C (8°F) and peaking at a maximum of 17°C (62°F), with an average temperature of just 1°C (35°F). Precipitation increases slightly to 89 mm (3.5 in) over the same number of days, but the humidity is higher at 92%. For more details on January weather, you can refer to Rheinfelden weather in January.

September weather typically showcases a broader temperature range, with minimums of 2°C (36°F) and maximums reaching 30°C (86°F), resulting in a pleasant average of 16°C (61°F). This month experiences around 69 mm (2.7 in) of precipitation over 12 days, while humidity tends to be around 83%. In contrast, February is much colder, with temperatures ranging from a minimum of -13°C (9°F) to a maximum of 19°C (66°F), giving an average of just 4°C (39°F). February also sees slightly more precipitation at 75 mm (2.9 in) over the same number of days, and humidity levels are slightly higher at 89%. For a closer look at February weather specifics, you can visit Rheinfelden weather in February.

September and March showcase a striking contrast in weather patterns. September enjoys milder temperatures, with averages around 16°C (61°F) and a maximum of 30°C (86°F), while March experiences chillier conditions, averaging just 6°C (44°F) and reaching a maximum of 21°C (71°F). Precipitation in March is slightly higher, totaling 87 mm (3.4 in) over 14 days, compared to September's 69 mm (2.7 in) across 12 days, and the humidity remains notably high in both months at 83% in September and 87% in March. For more detailed information on March weather, you can visit Rheinfelden weather in March.

In comparing the weather of September and April, we observe notable differences in temperature and precipitation patterns. September experiences a broader temperature range, with minimums around 2°C (36°F) and maximums reaching up to 30°C (86°F), resulting in a comfortable average of 16°C (61°F). In contrast, April tends to be cooler, with minimum temperatures dipping as low as -4°C (26°F) and averages around 10°C (50°F), peaking at only 26°C (80°F). Precipitation is somewhat similar, with September averaging 69 mm (2.7 in) over 12 days and April slightly lower at 59 mm (2.3 in) over 10 days. Humidity levels are comparable as well, with September at 83% and April just slightly higher at 84%. For more detailed insights, you can visit Rheinfelden weather in April.

September and May present distinct weather patterns, each with its own characteristics. In September, temperatures range from a minimum of 2°C (36°F) to a maximum of 30°C (86°F), with an average of 16°C (61°F). The month experiences around 69 mm (2.7 in) of precipitation over 12 days, combined with relatively high humidity at 83%. In contrast, May has a more moderate temperature range, with a minimum of 1°C (33°F) and a maximum of 31°C (87°F), averaging 14°C (57°F). However, it sees higher rainfall, totaling 126 mm (5.0 in) over 17 days, and maintains a slightly lower humidity level of 80%. For a detailed look at the weather characteristics in May, you can check Rheinfelden weather in May.

In comparing the weather of September and June, September tends to offer slightly cooler temperatures, with an average of 16°C (61°F) compared to June's 19°C (66°F). The maximum temperature in September reaches 30°C (86°F), while June can soar higher to 34°C (94°F). Both months have relatively high humidity, with September at 83% and June at 82%. However, June experiences more precipitation overall, with 120 mm (4.7 in) falling over 16 days, compared to September's 69 mm (2.7 in) over 12 days. For more detailed insights about June's weather, you can check Rheinfelden weather in June.

In comparing the weather between July and September, noticeable differences emerge in temperature and precipitation patterns. July boasts a broader range of temperatures, with a minimum of 9°C (49°F) and a maximum reaching up to 36°C (98°F), leading to an average of 20°C (69°F). However, it also experiences higher rainfall, totaling 122 mm (4.8 in) over 15 days. In contrast, September has cooler temperatures, with a minimum of 2°C (36°F) and a maximum of 30°C (86°F), averaging at 16°C (61°F). September sees 69 mm (2.7 in) of precipitation spread over 12 days, making it slightly drier than July. Despite this, both months share the same humidity level of 83%, creating a consistently moist atmosphere. For a more detailed look at July weather in Rheinfelden, you can refer to Rheinfelden weather in July.

In August, the weather is generally warmer, with average temperatures reaching 20°C (68°F) and maximums hitting 34°C (94°F), while September sees slightly cooler averages, with temps ranging from a minimum of 2°C (36°F) to a maximum of 30°C (86°F). August also experiences higher precipitation at 115 mm (4.5 in) over 15 days, compared to September's 69 mm (2.7 in) over 12 days. Both months have relatively high humidity, but September's level of 83% is a bit higher than August's 80%. For a closer look at the weather specifics for August, check this link: Rheinfelden weather in August.

In September, temperatures range from a mild 2°C (36°F) at night to a warm 30°C (86°F) during the day, with an average of 16°C (61°F). The month sees about 69 mm (2.7 in) of precipitation over 12 days, accompanied by a humidity level of 83%. In contrast, October experiences cooler temperatures, with nighttime lows dropping to -1°C (30°F) and daytime highs reaching 24°C (75°F), averaging 11°C (52°F). Rainfall increases slightly to 89 mm (3.5 in) spread over 13 days, and humidity rises to 90%. For more details about the weather in October, you can visit Rheinfelden weather in October.

In comparison to September, November experiences a significant drop in temperatures, with average highs falling to 5°C (42°F) from September’s warmer 16°C (61°F). While September can reach maximum temperatures of 30°C (86°F), November's maximum is notably cooler at 21°C (70°F). Precipitation levels are relatively similar, with September recording 69 mm (2.7 in) and November slightly higher at 73 mm (2.9 in), both occurring over 12 rainy days. Additionally, November's humidity increases slightly, reaching 88% compared to September’s 83%. For more detailed information about November weather, you can check Rheinfelden weather in November.

In September, the weather tends to be warmer, with average temperatures hovering around 16°C (61°F) and reaching highs of 30°C (86°F). The month experiences about 69 mm (2.7 in) of precipitation spread over 12 days, accompanied by a humidity level of 83%. In contrast, December brings a significant drop in temperatures, with average highs only reaching 3°C (38°F) and nighttime lows plummeting to -5°C (24°F). Precipitation is also more prevalent in December, with 124 mm (4.9 in) recorded over 18 days and a slightly higher humidity level of 90%. For more detailed information about the weather in December, you can visit Rheinfelden weather in December.

Compare Rheinfelden's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Rheinfelden

As September unfolds in Rheinfelden, the weather presents a delightful transition from the warm summer months to the cooler autumn days. This period is characterized by a notable variation in temperature, where daytime warmth gives way to much cooler nights, making it a unique time to experience the region's changing landscape. Though the humidity remains relatively high, the frequent rainfall, with an average of about 12 days of precipitation, adds a refreshing touch, nourishing the vibrant nature around. Compared to other months, September serves as a beautiful blend of lingering summer warmth and the crispness of autumn, inviting both residents and visitors to embrace the season's charm. For a deeper understanding of the overall climate in Rheinfelden, you can visit Rheinfelden Climate.