September Weather in Romanshorn, Switzerland

Last updated: August 27, 2025

September in Romanshorn, Switzerland, presents a pleasant transition into autumn, with temperatures ranging from a chilly 4°C (39°F) at night to a warm 26°C (80°F) during the day, averaging around 15°C (59°F). This month sees a total precipitation of 117 mm (4.6 in) spread over 12 days, contributing to the region's lush landscapes. The humidity level hovers around 83%, creating a refreshing atmosphere that enhances the picturesque beauty of Romanshorn. Experience the charm of early fall as the vibrant colors begin to emerge.

September Temperature in Romanshorn

In September, Romanshorn, Switzerland, transitions into a cozy autumn, showcasing a delightful range of temperatures. With minimums around 4°C (39°F) and comfortable averages peaking at 15°C (59°F), visitors can enjoy the crisp air while still basking in the remnants of summer warmth, as maximums reach a pleasant 26°C (80°F). This month marks a gradual cooling trend following the warmth of August, yet it retains a refreshing vibe that invites exploration of the scenic lakeside and charming town. As the days grow shorter, September offers a perfect blend of mild days and cooler evenings, making it an ideal time for outdoor activities and appreciating the stunning landscapes that embrace Romanshorn.

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

The chart illustrates September temperature patterns in Romanshorn, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Romanshorn, 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).
JanFebMarAprMayJunJulAugSepOctNovDec323641495665676659514236
Data source: Temperature data for Romanshorn 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 Romanshorn

In September, Romanshorn experiences a notable shift in precipitation patterns, receiving 117 mm (4.6 in) of rain over 12 days. This amount is a decline from the heavier downpours of August, which saw 175 mm (6.9 in), yet remains above the yearly average for the month. As summer fades, the precipitation becomes more consistent, transitioning from the intense summer storms to a gentler, more persistent rainfall. Notably, September marks the beginning of a gradual decrease in overall precipitation, leading into the drier months of late autumn. This month serves as a bridge, where the lush, wet summer gradually gives way to the milder, crisper air of fall, inviting a picturesque setting in this charming Swiss locale.

September Precipitation Trends in Romanshorn

The chart displays monthly precipitation patterns in Romanshorn, 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 Romanshorn, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec10983987614215214617511711873131
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Romanshorn

In Romanshorn, Switzerland, September marks a pivotal transition in humidity levels, registering at 83%. This slight rise from the previous month's average of 80% indicates the lingering warmth of late summer while hinting at the impending autumn chill. As the year progresses, humidity levels tend to fluctuate significantly, peaking in the winter months of January and December at 92% and 90% respectively. The overall trend showcases a gradual decrease from the high humidity of early winter, hitting its lowest point in May at 80%. Following this dip, early fall sees a modest uptick, suggesting that as nature prepares for the colder months, the air retains a hint of summer's moisture.

September Average Humidity in Romanshorn

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

As summer gives way to autumn in Romanshorn, Switzerland, the UV Index in September dips to 6, characterized as high exposure. This is a gentle decline from the soaring numbers seen in the peak summer months, where July and August registered a striking UV Index of 9. The return to a high level of UV means that sun protection remains vital, with a shorter burn time of 25 minutes compared to the intense 15 minutes earlier in the season. It's a reminder that even as temperatures cool, we should still be mindful of the sun's rays. For more details, check out Romanshorn UV Index.

Maximum UV Index Levels in Romanshorn for September

The chart shows the monthly maximum UV Index (UVI) for Romanshorn 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 Romanshorn typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec235689986431
Data source: Romanshorn 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 Romanshorn

September in Romanshorn, Switzerland, embraces the retreating warmth of summer as it enjoys an impressive 315 hours of sunshine. This month signifies a gentle transition, nestled between the peak brightness of July, which boasts 405 hours, and the subsequent tapering of light as autumn approaches in October with 276 hours. The trend is clear: as the year unfolds, sunshine hours gradually rise from the winter's low in January (154 hours) to a summer crescendo before settling into the softer hues of fall. September serves as a beautiful reminder of summer's lingering presence, inviting outdoor activities and scenic walks along the picturesque shores of Lake Constance.

Monthly Sunshine Duration in Romanshorn: September Highlighted

The September sunshine duration represents the total number of hours Romanshorn 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.
JanFebMarAprMayJunJulAugSepOctNovDec154h223h291h348h359h381h405h373h315h276h213h176h
Data source: Romanshorn September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Romanshorn During September

As summer fades into autumn, September brings a refreshing boost in sunshine to Romanshorn, Switzerland, with a 44% chance of clear days. This month stands out as one of the brighter periods of the year, surpassing the sunlit opportunities offered in the peak of summer, where the chances hover around 33% to 34%. Notably, as the weather transitions from the hot summer months to the cooler fall, September showcases an encouraging trend, thus inviting locals and visitors alike to embrace the outdoors before the colder months set in. While the month still grapples with the unpredictability of changing seasons, its hopeful sunshine quotient offers a delightful respite, making it an ideal time for engaging in outdoor activities and enjoying the scenic beauty of the region.

Percentage of Sunny Days in September in Romanshorn

The chart illustrates the percentage of sunny days in Romanshorn 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 Romanshorn experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec17%41%42%48%34%34%33%34%44%35%26%28%
Data source: Romanshorn September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Romanshorn in September

As summer transitions into autumn, September in Romanshorn, Switzerland brings a notable shift in daylight, with 12 hours of sunlight illuminating the days. This marks a gradual decrease from the peak daylight hours of 15 hours experienced during the heart of summer. While the fading light signals the onset of shorter days, September still offers ample opportunities for outdoor activities and enjoyment of the stunning Swiss landscapes. The daylight duration in September not only reflects the end of long summer evenings but also hints at the cozy, crisp days of autumn that are just around the corner, as the city prepares for the approaching chill of October with its 10 hours of daylight.

Average Daylight Hours in Romanshorn for September

The chart illustrates the variation in daylight duration in Romanshorn 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 14m11h 55m13h 39m15h 8m15h 54m15h 30m14h 10m12h 31m10h 48m9h 16m8h 28m
Data source: Romanshorn daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Romanshorn

As summer transitions to autumn, September in Romanshorn experiences a gentle dip in wind speeds, averaging 1.4 m/s (3 mph). This slight reduction follows a series of warmer months, where the winds picked up slightly in May before settling into a stillness throughout the later summer. Interestingly, September's winds are the calmest of the year, hinting at the tranquility that envelops the region as it prepares for fall. Looking ahead to October, the wind speeds remain comparable at 1.6 m/s (4 mph), suggesting a gradual return to more typical autumn breezes. This seasonal calm creates an inviting atmosphere, perfect for enjoying the serene beauty of Romanshorn's lakeside landscapes as nature shifts into a new chapter.

Average September Wind Speed in Romanshorn

The chart displays monthly wind speed patterns in Romanshorn, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.01.81.81.92.31.61.61.61.4 m/s1.61.71.9
Data source: Romanshorn September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Romanshorn Compares to Other Months

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

September and January present strikingly different weather experiences. In September, temperatures range from a chilly 4°C (39°F) at night to a pleasant 26°C (80°F) during the day, with an average of 15°C (59°F). This month sees significant precipitation, totaling 117 mm (4.6 inches) over about 12 days, accompanied by relatively high humidity at 83%. In contrast, January is marked by much colder conditions, with temperatures plunging to a minimum of -16°C (3°F) and an average of 0°C (33°F), only reaching a maximum of 13°C (55°F). Despite a slight decrease in precipitation to 109 mm (4.3 inches) over the same number of days, the humidity is even higher at 92%. For more specific details, you can explore Romanshorn weather in January.

September and February offer distinctly different weather experiences, reflecting the transition from late summer to winter. In September, temperatures range from a mild 4°C (39°F) at night to a warm 26°C (80°F) during the day, with an average of 15°C (59°F). The month typically sees 117 mm (4.6 in) of precipitation over about 12 days, accompanied by a comfortable humidity level of 83%. In contrast, February is much colder, with nighttime temperatures reaching a frigid -13°C (9°F) and daytime highs averaging around 2°C (37°F), peaking at 16°C (62°F). Despite a lower total precipitation of 83 mm (3.3 in) over the same number of days, the humidity is slightly higher at 89%. For more details about February weather, visit Romanshorn weather in February.

In comparing the weather of September and March, it's clear that March is notably colder with average temperatures hovering at 5°C (42°F), while September enjoys a milder average of 15°C (59°F). March experiences minimum temperatures that can plummet to -14°C (6°F), unlike September’s milder lows of 4°C (39°F). Both months see a fair amount of precipitation, with September recording 117 mm (4.6 in) over 12 days and March slightly less at 98 mm (3.8 in) spread over 16 days. Humidity remains relatively high in both months, with March at 87% and September at 83%. For a more detailed look at weather specifics, check Romanshorn weather in March.

When comparing the weather in September and April, some notable differences emerge. September typically enjoys milder temperatures, with a minimum of 4°C (39°F) and an average of 15°C (59°F), reaching a maximum of 26°C (80°F). In contrast, April can be significantly chillier, starting as low as -4°C (24°F) but averaging around 9°C (49°F), while peaking at 24°C (76°F). Precipitation levels in September are higher, reaching 117 mm (4.6 in) over 12 days, compared to April's 76 mm (3.0 in) spread across 9 days. Humidity remains relatively stable, with September at 83% and April slightly higher at 84%. For more details on April's weather specifics, you can check Romanshorn weather in April.

When comparing the weather in September and May, we observe notable differences in temperature and precipitation. September typically sees a minimum temperature of 4°C (39°F) and an average of 15°C (59°F), peaking at 26°C (80°F). In contrast, May starts with cooler temperatures, featuring a minimum of 0°C (32°F) and an average of 13°C (56°F), but can reach a maximum of 30°C (85°F). Precipitation levels are also higher in May, with 142 mm (5.6 in) over 16 days, compared to September's 117 mm (4.6 in) spread over 12 days. Humidity levels are relatively similar, with September at 83% and May at 80%. For a detailed look at what to expect, check Romanshorn weather in May.

When comparing the weather in September to that of June, we notice distinct differences in temperature and precipitation patterns. September exhibits a more moderate temperature range, with minimums around 4°C (39°F) and maximums reaching 26°C (80°F), averaging 15°C (59°F). In contrast, June features warmer temperatures, with minimums of 6°C (43°F), maximums soaring to 33°C (91°F), and an average of 18°C (65°F). Additionally, September tends to be less rainy, with 117 mm (4.6 in) of precipitation over 12 days, compared to June, which sees 152 mm (6.0 in) over 15 days. Humidity levels remain relatively similar, at 83% in September and 82% in June. For further details, you can check Romanshorn weather in June.

September and July present distinct contrasts in weather patterns. In September, temperatures range from a chilly minimum of 4°C (39°F) to a comfortable maximum of 26°C (80°F), with an average around 15°C (59°F). The month experiences significant rainfall, totaling 117 mm (4.6 in) over about 12 days, while humidity remains consistently high at 83%. In contrast, July boasts warmer temperatures, with a minimum of 11°C (51°F) and a high of 32°C (90°F), averaging 19°C (67°F). This month is wetter as well, seeing 146 mm (5.7 in) of precipitation over 16 days, yet maintains the same humidity level of 83%. For those interested in a closer look at July's weather, you can find more information here: Romanshorn weather in July.

In comparing the weather between September and August, September features cooler temperatures, with minimums dropping to 4°C (39°F) and an average of 15°C (59°F), while August enjoys milder conditions, starting at a minimum of 9°C (49°F) and an average of 19°C (67°F). August also experiences more heat, reaching maximum temperatures of 33°C (91°F), compared to September's peak of 26°C (80°F). Precipitation is more pronounced in August with 175 mm (6.9 in) over 14 days, while September sees a decrease in total rainfall to 117 mm (4.6 in) across 12 days. However, September's higher humidity level at 83% contrasts with August's slightly lower 80%. For more details on the August weather, you can visit Romanshorn weather in August.

September weather is characterized by a wider temperature range, with minimums around 4°C (39°F) and maximums reaching up to 26°C (80°F), giving an average of 15°C (59°F). In contrast, October experiences cooler temperatures, where the minimum drops to 1°C (34°F) and the average settles at 11°C (51°F), peaking at 22°C (72°F). Both months see comparable precipitation levels, with September recording 117 mm (4.6 in) over 12 days and October slightly higher at 118 mm (4.7 in) over 13 days. Additionally, October brings higher humidity at 90% compared to September's 83%. For more details on October weather, you can visit Romanshorn weather in October.

In September, the weather is typically mild, with average temperatures reaching around 15°C (59°F) and maximums peaking at 26°C (80°F). The month experiences considerable precipitation, totaling 117 mm (4.6 in) over approximately 12 days, along with a humidity level of 83%. In contrast, November brings a noticeable drop in temperatures, with an average of only 5°C (42°F) and a minimum dipping to -2°C (28°F). Although precipitation is less frequent, amounting to 73 mm (2.9 in) across roughly 11 days, humidity rises slightly to 88%. For a more detailed look at November's weather in Romanshorn, visit Romanshorn weather in November.

September and December present contrasting weather conditions. In September, temperatures range from a mild 4°C (39°F) at their lowest to a warm 26°C (80°F) at their highest, with an average temperature of 15°C (59°F). The month experiences about 117 mm (4.6 in) of precipitation over 12 days, accompanied by a relatively high humidity level of 83%. In contrast, December brings much colder weather, with temperatures ranging from a minimum of -9°C (16°F) to a maximum of 13°C (55°F), averaging just 2°C (36°F). Precipitation increases to 131 mm (5.2 in) over 19 days, alongside a slight rise in humidity to 90%. For a closer look at December weather specifics, check out Romanshorn weather in December.

Compare Romanshorn's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Romanshorn

As September unfolds in Romanshorn, it brings a noticeable shift in weather, gradually transitioning from the warmth of summer to the cooler embrace of autumn. With maximum temperatures reaching a pleasant 26°C, average daily highs lower to a comfortable 15°C, while the crisp mornings can plunge to a brisk 4°C. This month also sees a slight uptick in precipitation, with rain gracing about 12 days, contributing to the region's lush landscapes. Humidity stays relatively high at 83%, creating a unique blend of comfort and coolness. This combination of factors sets September apart from the hotter summer months, inviting residents and visitors alike to relish in the changing seasons. For a deeper understanding of the seasonal trends, visit Romanshorn Climate.