Last updated: August 27, 2025
In September, Rapperswil, Switzerland experiences a delightful transition into autumn, marked by a maximum temperature of 27°C (80°F) and an average of 14°C (57°F). As the days cool, nighttime temperatures can drop to a refreshing minimum of 2°C (36°F). Visitors can expect 123 mm (4.9 in) of precipitation throughout the month, occurring on 14 days, which adds a touch of charm to the scenic landscapes. With humidity levels at a comfortable 83%, September offers a blend of vibrant fall colors and cozy, brisk air, making it a picturesque time to explore this enchanting lakeside town.
September in Rapperswil, Switzerland, marks a delightful transition from the warmer summer months to the crispness of autumn. As temperatures begin to dip, you can expect minimums around 2°C (36°F) and pleasant averages of 14°C (57°F), with highs reaching a comfortable 27°C (80°F). This month is characterized by a gentle cooling trend, moving from the summer's peak warmth in August, where it maintained temperatures of up to 32°C (90°F). The landscape transforms, offering vibrant autumn foliage against a backdrop of cooler evenings, inviting both locals and visitors to enjoy outdoor activities and the serene beauty of the season.
In September, Rapperswil experiences a moderate rainfall of 123 mm (approximately 4.9 inches), marking a shift from the summer's wetter months. The precipitation occurs over 14 days, providing a balanced rhythm of wet and dry spells that often ushers in the vibrant autumn colors. This month, while slightly less rainy than the preceding August with its 158 mm, continues the trend of substantial rainfall typical of late summer. With the transition into fall, September's weather prepares the landscape for the upcoming cooler months, sustaining the lush greenery that characterizes this picturesque Swiss town.
In Rapperswil, Switzerland, September brings a slight uptick in humidity, recorded at 83%. This marks a small increase from the 80% seen in August, indicating a gradual transition as the summer warmth lingers into early fall. Notably, September's humidity is consistent with the trends observed in the preceding months of July and June, where levels hovered around 82-83%. As the year progresses towards the briskness of October, with humidity soaring to 90%, the gradual rise in September serves as a gentle reminder of the approaching autumn, where the air becomes richer and the landscapes prepare for a seasonal shift.
As autumn approaches in Rapperswil, Switzerland, the September UV Index presents a noticeable shift from the peak summer levels. With an index of 6, September falls into the high exposure category, allowing sun-seekers about 25 minutes of burn time before they need to seek shade or apply sunscreen. This decrease from the summer’s extreme figures indicates a transition towards more moderate sunlight levels, yet vigilance is still required, as UV radiation remains significant. As the year progresses, the UV Index continues to fluctuate, reminding us of the importance of sun safety year-round. For detailed UV trends throughout the year, explore Rapperswil UV Index.
UV Risk Categories
As the summer sun gradually bows out, September in Rapperswil, Switzerland, offers a gentle transition into autumn with 314 hours of sunlight—a notable drop from July’s peak of 410 hours. This month embraces a warm, golden glow, reflecting a rich tapestry of nature as it begins to show hints of fall. The trend reveals a steady decline in daylight hours as the year progresses, yet September delights with more sunlight than the colder autumn months ahead, such as October's 275 hours and November’s 211 hours. It’s a time when days are still long enough to enjoy the scenic beauty of Rapperswil, making it an ideal moment to savor the last remnants of summer before the crisp air sets in.
In Rapperswil, Switzerland, September offers a favorable transition toward autumn, boasting a 43% chance of sunny weather. This marks a slight uptick from the summer months, where the probabilities lingered around the low to mid-30s. Interestingly, September falls right after the peak sunny days of the spring and summer, hinting at a delightful balance of both warmth and crispness in the air. As the summer heat subsides, the weather starts to become more temperate, making it an ideal time for outdoor activities amidst the ongoing beauty of the season. With a slightly higher likelihood of sunshine compared to October’s 41%, September stands out as a charming month to relish the picturesque landscapes of this scenic Swiss town.
As summer fades into autumn, September in Rapperswil, Switzerland greets residents with a gentle decline in daylight, offering approximately 12 hours of sunshine. This transition marks a shift from the peak summer months, where daylight extended delightfully to 15 hours in June, July, and part of August. The gradual reduction in daylight hours, from the vibrant 15 hours in August to 12 hours this month, signals the approach of autumn and prepares the landscape for the changing hues of fall. Following a brief September, daylight will further diminish, dwindling to 10 hours in October, creating a rhythmic pattern that beautifully reflects the change of seasons in this picturesque town.
In Rapperswil, Switzerland, the September winds settle into a gentle rhythm, with an average speed of 1.5 m/s (3 mph), mirroring the lighter breezes of the preceding summer months. This slight decline in wind speed reflects a broader trend observed throughout the warmer season, where the winds tend to be calmer with July and August both registering at the same tranquil pace. As autumn approaches, the breeze begins to pick up slightly in October, hinting at the shifts to come. Overall, September's moderate wind serves as a serene bridge between the warmth of late summer and the crispness of fall, inviting residents and visitors alike to enjoy the picturesque lakeside views without the distractions of harsher gusts.
Weather in Rapperswil varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Rapperswil, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present stark contrasts in weather, highlighting the transition from late summer to winter. In September, temperatures range from a minimum of 2°C (36°F) to a comfortable maximum of 27°C (80°F), with an average of 14°C (57°F), while January typically sees much colder conditions with temperatures plunging to a minimum of -12°C (10°F) and averaging around 0°C (32°F), peaking at a mere 13°C (56°F). Both months experience considerable precipitation, with September receiving 123 mm (4.9 in) over 14 days and January close behind at 127 mm (5.0 in) over 12 days. Additionally, humidity is higher in January at 92% compared to 83% in September. For more details about January conditions, visit Rapperswil weather in January.
September and February showcase stark contrasts in climate. In September, temperatures range from a mild 14°C (57°F) on average to a pleasant high of 27°C (80°F), providing a warm and inviting atmosphere, although it also experiences significant precipitation with around 123 mm (4.9 in) over approximately 14 days. In contrast, February presents a much colder landscape, with average temperatures plummeting to just 2°C (36°F), and nighttime lows dropping to -15°C (6°F). While it sees slightly less precipitation at 95 mm (3.7 in) over about 12 days, humidity remains high at 89%. For a detailed look at February conditions, visit Rapperswil weather in February.
When comparing the weather in September and March, distinct differences emerge. September experiences milder temperatures, ranging from a minimum of 2°C (36°F) to a comfortable maximum of 27°C (80°F), making it feel much warmer overall, with an average temperature of 14°C (57°F). However, it also sees a fair amount of rainfall, with 123 mm (4.9 in) of precipitation over 14 days and a humidity level of 83%.
In contrast, March is significantly colder, with temperatures ranging from a minimum of -16°C (4°F) to a maximum of 19°C (67°F), leading to an average temperature of just 4°C (40°F). Although it has slightly less precipitation at 112 mm (4.4 in), it occurs over more days, with rain or snow falling on 17 days, and a slightly higher humidity of 87%.
For a detailed look at Rapperswil's climate during this time, you can check out the Rapperswil weather in March.
When comparing the weather in September and April, a notable difference is observed in temperature. September typically sees milder conditions, with average temperatures around 14°C (57°F) and a maximum that can reach up to 27°C (80°F). In contrast, April starts off much cooler, with average highs of only 8°C (47°F) and even lower minimum temperatures dropping to -7°C (19°F). Precipitation levels are also significant, with September receiving more rain at 123 mm (4.9 in) over 14 days, while April has less at 87 mm (3.4 in) across 12 days. Humidity levels remain relatively consistent, with September at 83% and April slightly higher at 84%. For more details on April weather specifics, check out Rapperswil weather in April.
Comparing the weather in September and May reveals some interesting contrasts. September typically enjoys milder temperatures with a minimum of 2°C (36°F) and an average of 14°C (57°F), while May can start off chillier, with lows reaching -5°C (24°F), although it can also peak at a maximum of 28°C (84°F). Precipitation is more frequent in May, with rain falling on about 20 days and totaling 159 mm (6.3 in), compared to September's 123 mm (4.9 in) over 14 days. Despite this, both months experience relatively high humidity levels, around 83% in September and 80% in May. For more details on the specifics of May weather, check out Rapperswil weather in May.
Comparing the weather in September and June reveals some notable differences. In June, temperatures range from a minimum of 4°C (40°F) to a maximum of 32°C (90°F), with an average temperature of 17°C (63°F), making it generally warmer than September, where the temperatures vary from 2°C (36°F) to 27°C (80°F) and average at 14°C (57°F). Additionally, June experiences higher precipitation levels, with 187 mm (7.4 in) over 17 days, compared to September's 123 mm (4.9 in) over 14 days. Humidity remains relatively similar, around 83% in September and 82% in June. For more detailed information, you can visit Rapperswil weather in June.
When comparing the weather in September to that of July, notable differences emerge. September tends to be cooler, with minimum temperatures dipping to 2°C (36°F), while July enjoys a milder average minimum of 8°C (47°F). The average temperature in September reaches only 14°C (57°F), significantly lower than July's 18°C (65°F). Additionally, July experiences a higher maximum temperature of 33°C (91°F) compared to September's peak of 27°C (80°F). Both months have similar humidity levels at 83%, but July sees slightly more precipitation, totaling 145 mm (5.7 in) over 16 days, while September receives 123 mm (4.9 in) over 14 days. For more details about July weather in Rapperswil, please check Rapperswil weather in July.
In comparing the weather between August and September, August generally experiences warmer temperatures, with a minimum of 8°C (46°F) and an average of 18°C (65°F), reaching a maximum of 32°C (90°F). In contrast, September cools down significantly, featuring a minimum of 2°C (36°F) and an average of 14°C (57°F), peaking at 27°C (80°F). Although September is slightly wetter, with 123 mm (4.9 in) of precipitation over 14 days compared to August's 158 mm (6.2 in) across 15 days, humidity remains relatively high in both months, at 83% for September and 80% for August. For a more detailed outlook on August weather, you can check Rapperswil weather in August.
September and October present a noticeable shift in weather patterns. In September, temperatures range from a minimum of 2°C (36°F) to a maximum of 27°C (80°F), with an average of 14°C (57°F), and the month experiences 123 mm (4.9 in) of precipitation over 14 days, accompanied by a relatively high humidity of 83%. In contrast, October sees cooler conditions, with temperatures dropping to a minimum of 0°C (32°F) and a maximum of 22°C (72°F), averaging 10°C (50°F). Precipitation slightly increases to 128 mm (5.0 in) over 13 days, and humidity rises to 90%. This transition marks a movement towards a more autumnal climate, with October's chill and moisture preparing for the coming winter. For more detailed information, check out Rapperswil weather in October.
In comparing the weather of September and November, one can observe notable differences in temperature and precipitation. September enjoys a milder average temperature of 14°C (57°F), with maximums reaching up to 27°C (80°F), whereas November's average drops significantly to 4°C (40°F), with highs only reaching 20°C (69°F). Additionally, September is marked by higher precipitation at 123 mm (4.9 in) over 14 days, compared to November's 80 mm (3.1 in) over 13 days. Humidity levels are slightly higher in November at 88%, compared to September's 83%. For more detailed weather insights, you can refer to Rapperswil weather in November.
In September, the weather is generally milder, with temperatures ranging from a minimum of 2°C (36°F) to a maximum of 27°C (80°F) and an average temperature of 14°C (57°F). The month sees around 123 mm (4.9 in) of precipitation over 14 days, with humidity levels at 83%. In contrast, December brings much colder conditions, with temperatures dropping significantly, characterized by a minimum of -10°C (14°F) and a maximum of 12°C (54°F), resulting in an average temperature of just 2°C (35°F). Precipitation increases to 155 mm (6.1 in) over 19 days, along with higher humidity at 90%. For more detailed information about December weather, check out Rapperswil weather in December.
As summer gracefully fades into autumn, September in Rapperswil showcases a blend of warmth and coolness, making it a unique transition month. With average temperatures dipping from the summer highs, it offers a comfortable respite with a mix of sunny days and breezy evenings. However, the month also comes with increased precipitation, featuring around 14 rainy days that add a touch of freshness to the atmosphere. Despite the 83% humidity, the vibrant autumnal colors begin to emerge, creating a picturesque backdrop for outdoor activities. For detailed insights into the region's weather patterns throughout the year, visit Rapperswil Climate.