Last updated: August 27, 2025
In September, Sankt Gallen, Switzerland, experiences a delightful transition from summer to autumn. With maximum temperatures reaching 27°C (80°F) and an average of 15°C (59°F), the region enjoys pleasantly warm days, while cooler nights can plunge to a refreshing 4°C (40°F). However, this month also brings its share of rain, accumulating 128 mm (5.0 in) across approximately 13 days, resulting in a humidity level of 83% that enhances the crisp air. Those who embrace the shifting seasons will find Sankt Gallen's September both invigorating and beautifully lush, showcasing the enchanting charm of this Swiss locale.
In September, Sankt Gallen welcomes the onset of autumn with a refreshing transition in temperatures. The month begins with a minimum of 4°C (40°F) and an inviting average of 15°C (59°F), reaching a comfortable high of 27°C (80°F). Compared to the summer months of July and August, where maximum temperatures hovered around 33°C (91°F), September provides a noticeable cool down, ushering in a more temperate climate that encourages outdoor activities. This shift not only heralds the changing leaves but also offers a perfect blend of warmth and crispness, making it an ideal time to explore the scenic beauty and rich culture of the region.
September in Sankt Gallen, Switzerland, showcases a significant shift in precipitation patterns, marking the arrival of autumn. With 128 mm (5.0 in) of rainfall spread over 13 days, September continues the trend of increased moisture seen in the preceding summer months. While slightly less than the heavy downpours of August, this month still maintains a robust level of precipitation, contributing to the lush landscapes typical of the region. This consistent rainfall sets the stage for the cooler months ahead, as September's totals bridge the gap between the warm, wet summer and the crisp, drier days of fall. As the year transitions, the changing patterns in precipitation remind us of the dynamic climate that defines Sankt Gallen.
As summer transitions into autumn, September in Sankt Gallen, Switzerland, enjoys a moderate humidity level of 83%, providing a comfortable atmosphere for outdoor enthusiasts. This slight increase from August's 80% marks a gradual rise that continues as the year progresses, culminating in higher readings during the colder months, with October peaking at 90%. Throughout the year, Sankt Gallen experiences its highest humidity in the winter months, with January and December both hovering around 92%. The data reveals a clear trend of decreasing humidity as spring approaches, hitting its lowest point in May at 80%. This cyclical pattern reflects the region's distinct seasonal changes, making September a pleasantly humid month before the chill sets in.
As September arrives in Sankt Gallen, Switzerland, the UV Index sees a slight decline to 6, categorizing the exposure as high. This transition reflects the shift from summer's peak UV levels, which soared to 9 in July and June, down to a more moderate yet still significant level. With a burn time of 25 minutes, it's essential to remain vigilant about sun protection, even as the days begin to shorten. September's UV Index highlights the importance of adjusting sun safety measures as summer recedes while still enjoying the outdoors. For more detailed insights, check the Sankt Gallen UV Index.
UV Risk Categories
As September rolls into Sankt Gallen, the city continues to bask in the warmth of summer's lingering embrace, offering an impressive 315 hours of sunshine. This abundant sunlight marks a gradual decline from the peak of 404 hours in July, yet it remains significantly brighter than the wintry months ahead. The transition into autumn is gentle, with September maintaining a vibrant glow that continues to nurture the lush landscapes. After a steady rise from 150 hours in January to a sun-drenched 356 hours in May, the year's light begins to ebb, hinting at the cozy, reflective days of October. As the days shorten, Sankt Gallen showcases a picturesque blend of late summer warmth and the first whispers of fall, making September a delightful moment for both residents and visitors to enjoy the outdoors.
As September rolls in Sankt Gallen, Switzerland, the likelihood of sunny weather begins to pick up, with a 43% chance of sunshine—a notable increase compared to the summer months. This upward trend in sunshine probabilities from the previous months, where July and August hover around 33-34%, suggests a transition towards more favorable weather as the region bids farewell to the peak summer heat. Interestingly, this slight rise in sunshine chances positions September as a relatively promising time for outdoor pursuits before autumn sets in, standing out in contrast to the grey and overcast months that follow, like November and December with their 24% and 27% chances respectively. So, if you’re planning a visit, expect September to offer a refreshing glimpse of sunshine amidst the gradual shift toward cooler, cloudier days ahead.
As summer fades in Sankt Gallen, September marks a transition with 12 hours of daylight—a gentle decline from the long, sunlit days of summer. Following the peak brightness of June through August, where daylight consistently reached up to 15 hours, the shorter days signal the impending autumn. This month serves as a bridge, easing the shift toward the shorter daylight hours of October, which sees a further reduction to 10 hours. The gradual decrease in sunlight invites residents and visitors alike to savor the late summer warmth while preparing for the cozy embrace of fall, highlighting a rhythm of light that shapes life in this charming Swiss town.
In September, the winds in Sankt Gallen take a gentle turn, with an average speed of just 1.6 m/s (3 mph), marking it as one of the calmest months of the year. This tranquil breeze follows a pattern observed throughout the summer, where wind speeds have remained relatively low, averaging around 1.7 to 1.8 m/s from June to August. Interestingly, the transition from the vibrant summer months to the cool embrace of autumn is subtle, as September's winds signal the onset of shifting seasons. As the year progresses into October and November, a slight uptick in wind speed occurs, suggesting a gradual return to more blustery autumn conditions that can invigorate the landscape. In this picturesque Swiss town, the September wind offers a peaceful pause before the gusts of fall begin to stir.
Weather in Sankt Gallen varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Sankt Gallen, focusing on differences in temperature, rainfall, humidity, and UV levels.
In September, the weather in Sankt Gallen is generally mild, with average temperatures ranging from a minimum of 4°C (40°F) to a maximum of 27°C (80°F) and an average of 15°C (59°F). The month sees about 128 mm (5.0 in) of precipitation over 13 days, and humidity levels are relatively high at 83%. In contrast, January brings much colder temperatures, with an average low of -14°C (7°F) and a maximum of 14°C (57°F), resulting in an average temperature of 0°C (33°F). While precipitation decreases slightly to 106 mm (4.2 in) over 12 days, the humidity rises to 92%, contributing to the winter chill. For a more detailed look at the weather during this month, check out Sankt Gallen weather in January.
September and February present strikingly different weather conditions. In September, temperatures range from a minimum of 4°C (40°F) to a maximum of 27°C (80°F), with an average of 15°C (59°F). The month experiences relatively high humidity at 83% and rainfall of 128 mm (5.0 in) over 13 days. Conversely, February is much colder, featuring temperatures that drop to -13°C (9°F) at night and reach a maximum of 18°C (65°F) during the day, averaging just 2°C (37°F). This month sees less precipitation at 85 mm (3.3 in) over 12 days, but humidity remains high at 89%. For more detailed information, you can check Sankt Gallen weather in February.
September and March exhibit stark contrasts in weather. September typically enjoys milder temperatures with a minimum of 4°C (40°F) and an average of 15°C (59°F), peaking at a warm 27°C (80°F). In contrast, March is still firmly in the grip of winter with much colder temperatures, including a minimum of -14°C (8°F) and an average of only 5°C (42°F), reaching a maximum of 19°C (66°F). Rainfall in September is relatively high at 128 mm (5.0 in) over 13 days, while March sees slightly less precipitation at 100 mm (3.9 in) across 16 days. Additionally, March is characterized by higher humidity at 87%, compared to September's 83%. For more details, you can check Sankt Gallen weather in March.
September and April present distinct weather patterns, reflecting the transition between the end of summer and the onset of spring. In September, temperatures range from a minimum of 4°C (40°F) to a maximum of 27°C (80°F), with an average of 15°C (59°F), making it generally warmer than April, which sees a minimum of -6°C (22°F) and a maximum of 24°C (76°F) with an average of 9°C (49°F). Precipitation levels are higher in September, with 128 mm (5.0 in) recorded over 13 days, compared to April's 79 mm (3.1 in) over 11 days. Both months have similar humidity levels, with September at 83% and April slightly higher at 84%. For more detailed information on April weather, you can check Sankt Gallen weather in April.
When comparing the weather in September and May, both months exhibit mild temperatures and a noticeable amount of precipitation. September typically has a wider temperature range, with a minimum of 4°C (40°F) and a maximum of 27°C (80°F), averaging around 15°C (59°F). In contrast, May's temperatures are slightly cooler on average at 13°C (56°F), with a minimum of 0°C (32°F) and a maximum reaching 29°C (85°F). Although May sees a higher total precipitation of 147 mm (5.8 in) over 17 days compared to September's 128 mm (5.0 in) over 13 days, both months maintain a relatively high humidity level, with September at 83% and May at 80%. For more detailed insights on May weather, you can visit Sankt Gallen weather in May.
In comparing the weather between September and June, we see notable differences in temperature, precipitation, and humidity. September experiences cooler temperatures with a minimum of 4°C (40°F) and a maximum of 27°C (80°F), while June boasts a warmer range, starting at 7°C (44°F) and reaching up to 32°C (91°F). Precipitation is slightly higher in June, averaging 168 mm (6.6 in) over 17 days, compared to September’s 128 mm (5.0 in) over 13 days. Interestingly, both months have similar humidity levels, hovering around 82-83%. For more detailed information about June weather, you can visit Sankt Gallen weather in June.
When comparing the weather in September and July, it's evident that July is generally warmer, with average temperatures ranging from a minimum of 10°C (51°F) to a maximum of 33°C (91°F). In contrast, September sees a cooler range, with temperatures dipping as low as 4°C (40°F) and peaking at 27°C (80°F). Additionally, July experiences slightly more precipitation, totaling 159 mm (6.3 in) over 18 days, compared to September's 128 mm (5.0 in) across 13 days. Interestingly, both months maintain a consistent humidity level of 83%, indicating that regardless of the temperature, the air retains a similar moisture content. For a more detailed look at July weather specifics, you can check Sankt Gallen weather in July.
In comparing the weather of September and August, September experiences cooler temperatures overall, with a minimum of 4°C and an average of 15°C, while August starts warmer, with a minimum of 9°C and an average of 19°C. The maximum temperatures in September peak at 27°C, compared to a hotter 33°C in August. Additionally, September sees more rainy days, with precipitation spread over 13 days and totaling 128 mm, compared to 194 mm over 17 days in August. Humidity remains relatively high in both months, at 83% in September and 80% in August. For more detailed information, you can refer to Sankt Gallen weather in August.
As September transitions into October, the weather notably cools down. September boasts a wider range of temperatures, with a minimum of 4°C (40°F) and a maximum of 27°C (80°F), averaging around 15°C (59°F). In contrast, October sees a drop in average temperature to 10°C (51°F), with minimums reaching 2°C (35°F) and maximums peaking at 23°C (73°F). Precipitation remains somewhat consistent, with September receiving 128 mm (5.0 in) over 13 days, while October accumulates slightly less at 119 mm (4.7 in) over 14 days. Additionally, October is characterized by higher humidity levels at 90%, compared to September's 83%. For more detailed information, check out Sankt Gallen weather in October.
September and November offer contrasting weather patterns. In September, the temperatures range from a mild minimum of 4°C (40°F) to a warm maximum of 27°C (80°F), with an average of 15°C (59°F). This month also sees relatively high precipitation, totaling 128 mm (5.0 in) across about 13 days, alongside a humidity level of 83%. In contrast, November experiences cooler conditions, with temperatures dropping to a minimum of -2°C (29°F) and averaging 5°C (42°F), while the maximum reaches 19°C (67°F). Precipitation is lower at 72 mm (2.8 in) across 11 days, and humidity increases slightly to 88%. For more detailed insights into November weather, you can visit Sankt Gallen weather in November.
September and December weather present a striking contrast in Sankt Gallen. In September, temperatures range from a mild 4°C (40°F) at night to a warm 27°C (80°F) during the day, with an average of 15°C (59°F). The month sees about 128 mm (5.0 in) of precipitation over 13 days and humidity levels around 83%. By December, however, the climate shifts dramatically, with temperatures plummeting to a low of -7°C (19°F) and peaking at a much cooler 12°C (54°F), averaging just 2°C (36°F). December also witnesses increased precipitation at 135 mm (5.3 in) over 18 days, alongside higher humidity at 90%. For more details, you can check Sankt Gallen weather in December.
As September unfolds in Sankt Gallen, the weather begins to transition from the summer warmth towards the crispness of autumn. With average temperatures settling around 15°C (59°F) and a peak of 27°C (80°F), the month promises delightful days, especially in its early weeks. However, the increase in humidity, reaching 83%, and a noticeable surge in precipitation, totaling 128 mm over 13 days, signal the start of the wetter season. This combination creates a refreshing yet unpredictable climate, offering a stark contrast to the warmer and drier summer months. For those keen on exploring the unique aspects of Sankt Gallen's weather, you can learn more about this city's seasonal nuances by visiting Sankt Gallen Climate.