Last updated: August 27, 2025
Experience the enchanting September weather of Arosa, Switzerland, where the mountains cradle a unique climate. With daytime maximum temperatures reaching a mild 20°C (68°F), you can enjoy crisp, refreshing air. The average temperature hovers around 7°C (46°F), offering a cool respite, while the nights can dip to a chilly -11°C (13°F). September also sees 134 mm (5.3 in) of precipitation spread over 16 days, ensuring the lush landscapes remain vibrant. With humidity levels sitting at a cozy 83%, this picturesque alpine town invites visitors to revel in its stunning autumn charm.
In September, Arosa, Switzerland, ushers in a refreshing transition towards autumn. With temperatures ranging from a chilly -11°C (13°F) at night to a pleasant 20°C (68°F) during the day, this month offers a delightful blend of cool mountain air and the lingering warmth of summer. The average temperature settles around 7°C (46°F), providing a comfortable backdrop for outdoor activities amidst the stunning autumnal landscapes. As the days grow shorter and the crispness in the air intensifies, September serves as a beautiful bridge, heralding the shift from the sun-soaked days of summer to the cozy embrace of fall, making it an ideal time for visitors to explore Arosa's breathtaking scenery.
September in Arosa, Switzerland, sees a marked transition in weather patterns, with precipitation reaching 134 mm (5.3 in) over 16 days. This follows the wetter months of summer, particularly August, which brought a hefty 197 mm of rain. The moderate drop in rainfall from August to September suggests the onset of autumn, as days become cooler and more variable. Nonetheless, September still maintains a healthy volume of rainfall, typical of the region's mountainous climate. This month sets the stage for the autumn foliage to emerge, making Arosa a picturesque destination even amidst its frequent showers.
In September, Arosa experiences a notable shift in humidity, settling at 83%. This marks a slight increase from the summer months of July and August, where humidity levels hovered around 80-83%. As the transition into autumn begins, the consistent presence of higher humidity levels throughout the year, peaking again in October at 90%, indicates the region's characteristic dampness. The overall trend shows a gradual decline in humidity from January's staggering 92%, culminating in the more moderate levels during the summer, before rising again as winter approaches. Thus, September serves as a bridge, linking the warm, dry months of summer to the cooler, moister climate of fall.
As September arrives in Arosa, Switzerland, the UV Index shows a notable decline, dropping to 7, categorized as high, with a burn time of 25 minutes. This marks a transition from the peak summer months, where the Index reached its highest levels of 10 in June and July, indicating very high exposure risk. While the level does decrease compared to the scorching heat of summer, sun protection remains essential as the days gradually shorten and cool. Overall, September invites outdoor enthusiasts to enjoy the crisp alpine air while remaining mindful of their sun exposure. For more detailed insights, visit Arosa UV Index.
UV Risk Categories
As summer fades, September in Arosa, Switzerland, continues to bask in the golden glow of sunshine, boasting 309 hours of radiant light. The month transitions gracefully from the peak of summer, where July shines bright with 408 hours, to an early autumn tapestry enriched by the crisp mountain air. As the sunny days of June and July give way to the softer warmth of September, the daylight begins to retreat, signaling the onset of fall. Yet, with 309 hours still illuminating the landscape, this month provides a perfect opportunity for outdoor adventures before winter sets in. Observing this gradual decline in daylight hours offers a glimpse into Arosa's seasonal charm, where each month brings its own unique brilliance.
In September, Arosa, Switzerland experiences a 35% chance of sunny weather, marking a slight increase compared to the summer months of July and August, which hover around 31% and 30% respectively. As autumn begins to set in, this moderate probability suggests that while sunny days are still possible, they become less frequent as the season transitions. Interestingly, September's sunshine likelihood is on par with the overall trends seen earlier in the year, with October also showing a 37% chance. This provides a promising window for visitors looking to enjoy the picturesque Swiss landscape basked in sunlight before colder months arrive, aligning nicely with the desire for outdoor adventures amidst the stunning alpine scenery.
As summer fades and autumn approaches in Arosa, Switzerland, the daylight duration exhibits a captivating transition. September marks a gradual decline to 12 hours of daylight, signaling the shift from the vibrant long days of summer, which boast up to 15 hours in June, July, and August. This decrease is a gentle precursor to the shorter days of fall, with October dropping to 10 hours and continuing the trend into the winter months. As nature prepares for the colder seasons, the daylight hours create a rhythm, inviting residents and visitors alike to embrace the changing scenery and the beauty of Arosa's alpine landscapes.
In Arosa, Switzerland, the September winds tend to mimic the gentle breezes of late summer, averaging a modest 1.3 m/s (3 mph). As the summer wanes, this slight wind speed is part of a broader trend observed throughout the year, where the winds typically hover around similar levels, with peaks in October and February at 1.6 m/s (4 mph). This consistency underscores September's transitional nature, where the year’s most serene gusts linger, providing a calm prelude to the crisp autumn air. Overall, the gentle winds of early autumn in Arosa create a tranquil atmosphere that perfectly complements the breathtaking alpine scenery.
Weather in Arosa varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Arosa, focusing on differences in temperature, rainfall, humidity, and UV levels.
In September, the weather is relatively mild, with temperatures ranging from a chilly -11°C (13°F) to a pleasant max of 20°C (68°F) and an average of around 7°C (46°F). During this month, precipitation is quite significant, totaling 134 mm (5.3 in) over about 16 days, accompanied by a moderate humidity level of 83%. In contrast, January brings a much colder climate, with temperatures plummeting to a minimum of -30°C (-21°F) and an average of -9°C (16°F), peaking at just 5°C (40°F). Precipitation decreases to 92 mm (3.6 in) over 11 days, while humidity rises slightly to 92%. For more detailed information, you can check Arosa weather in January.
September and February present stark contrasts in weather. In September, temperatures range from a chilly -11°C (13°F) at night to a pleasant high of 20°C (68°F) during the day, with an average of 7°C (46°F). The month experiences considerable precipitation, totaling 134 mm (5.3 in) over 16 days, accompanied by a humidity level of 83%. In contrast, February is considerably colder, with minimum temperatures plunging to -26°C (-14°F) and averaging -6°C (22°F), while maximum temperatures reach only 9°C (48°F). Precipitation is less frequent in February, amounting to 65 mm (2.6 in) across 12 days, and the humidity rises slightly to 89%. For more detailed insights, you can check out Arosa weather in February.
September and March present quite contrasting weather conditions. In September, temperatures range from a chilly minimum of -11°C (13°F) to a pleasant maximum of 20°C (68°F), with an average of 7°C (46°F). The month sees significant precipitation, totaling 134 mm (5.3 in) over 16 days, alongside a humidity level of 83%. In contrast, March is notably colder, with temperatures dipping as low as -26°C (-14°F) and peaking at only 11°C (52°F), averaging -3°C (27°F). The precipitation in March is relatively lower at 92 mm (3.6 in) spread over the same number of days, while humidity slightly increases to 87%. For a more detailed look at March weather, check Arosa weather in March.
September and April present contrasting weather patterns, with April generally being colder than September. In September, temperatures fluctuate between a minimum of -11°C (13°F) and a maximum of 20°C (68°F), resulting in a more moderate average of 7°C (46°F). In contrast, April experiences lower temperatures, ranging from a chilling minimum of -24°C (-11°F) to a maximum of 15°C (59°F), leading to an average just above freezing at 1°C (34°F). Precipitation is higher in September, totaling 134 mm (5.3 in) over 16 days, while April sees 87 mm (3.4 in) over 14 days, making September a wetter month. Despite these differences, both months maintain similar humidity levels, with September at 83% and April at 84%. For more detailed insights into April’s climate, you can refer to Arosa weather in April.
In September, the weather in Arosa features a more moderate temperature range, with a minimum of -11°C (13°F), an average of 7°C (46°F), and a maximum of 20°C (68°F). The month experiences significant precipitation, totaling 134 mm (5.3 in) over about 16 rainy days, and maintains a high humidity level of 83%. Conversely, May presents slightly colder conditions, with a minimum of -13°C (9°F) and an average of 5°C (41°F), although it can peak at 21°C (69°F). Precipitation is also higher in May, reaching 161 mm (6.3 in) over 23 days, but with a slightly lower humidity of 80%. These differences highlight the transition in weather from the end of summer to the beginning of spring, making Arosa an intriguing location year-round. For more details, check Arosa weather in May.
In comparing the weather of September and June, a distinct contrast emerges. September experiences a wider temperature range, with minimums dropping to -11°C (13°F) and maximums reaching 20°C (68°F), averaging around 7°C (46°F). It also boasts higher humidity at 83%, accompanied by 134 mm (5.3 in) of precipitation over 16 days. In contrast, June offers milder conditions, with temperatures ranging from a minimum of -2°C (28°F) to a maximum of 26°C (79°F) and an average of 10°C (51°F). Although June sees a slight increase in overall precipitation (147 mm or 5.8 in) over 19 days, its humidity remains relatively stable at 82%. For more details about June weather in Arosa, you can visit Arosa weather in June.
In September, the weather is notably cooler than in July, with average temperatures ranging from a chilly -11°C (13°F) at night to a milder 20°C (68°F) during the day. In contrast, July boasts warmer temperatures, with lows of 2°C (36°F) and highs reaching 25°C (78°F). Both months experience significant precipitation, with September receiving 134 mm (5.3 in) over 16 days and July slightly wetter at 152 mm (6.0 in) over 20 days. Interestingly, humidity levels remain constant at 83% for both months, adding a similar feel to the air despite the temperature differences. For a closer look at July's weather, you can visit Arosa weather in July.
In September, the weather starts to cool down significantly, with temperatures ranging from a minimum of -11°C (13°F) to a maximum of 20°C (68°F), averaging around 7°C (46°F). This marks a noticeable drop compared to August, where temperatures ranged from 0°C (31°F) to 23°C (74°F), averaging 11°C (52°F). Additionally, September experiences higher precipitation with 134 mm (5.3 in) over 16 days, compared to August's 197 mm (7.8 in) over 20 days. Humidity levels remain relatively high in both months, soaring to 83% in September and slightly lower at 80% in August. For more detailed insights on August conditions, you can check Arosa weather in August.
In comparing the weather between September and October, it's evident that both months experience cool conditions but with some distinct differences. September typically offers slightly warmer temperatures, with averages around 7°C (46°F) and a maximum of 20°C (68°F), while October sees a drop, averaging around 3°C (39°F) and peaking at 16°C (61°F). Interestingly, both months have comparable precipitation levels, with September registering 134 mm (5.3 in) over 16 days and October slightly lower with 133 mm (5.3 in) across 12 days. Humidity increases in October, rising to 90% compared to September's 83%, contributing to a more pronounced chill in the air. For more details on the weather during this time, you can visit Arosa weather in October.
In September, the weather is generally milder, with temperatures ranging from a minimum of -11°C (13°F) to a maximum of 20°C (68°F) and an average of 7°C (46°F). The month experiences significant rainfall, with a total precipitation of 134 mm (5.3 in) over approximately 16 days, and the humidity sits at 83%. In contrast, November brings noticeably colder temperatures, with a minimum of -21°C (-5°F), an average of -3°C (27°F), and a maximum of 12°C (55°F). While November sees slightly less rainfall at 103 mm (4.0 in) across 13 days, the humidity increases to 88%, contributing to the overall chill in the air. For more specifics on November weather, you can check Arosa weather in November.
The weather in September is notably milder compared to December, with temperatures ranging from a chilly -11°C (13°F) at night to a comfortable maximum of 20°C (68°F) during the day, resulting in an average temperature of 7°C (46°F). In contrast, December brings much colder conditions, with nighttime lows plummeting to -27°C (-17°F) and daytime highs only reaching 4°C (40°F), leading to an average temperature of -7°C (19°F). Both months experience a similar amount of precipitation, around 134 mm (5.3 in) in September and slightly less at 129 mm (5.1 in) in December, with precipitation occurring on 16 days in each month. While September has a humidity level of 83%, December sees an increase to 90%. For more specific details on December weather, you can check out Arosa weather in December.
As summer fades into autumn, Arosa's September weather presents a distinct contrast to the warmer months that precede it. With average temperatures dipping and a noticeable increase in precipitation, visitors can expect a more chilly and moist atmosphere compared to July and August's warmth. The humidity remains high, adding to the crispness in the air, making it an ideal time for those who appreciate the beauty of changing seasons and the tranquil ambiance that comes with them. For further insights into the overall climate patterns, explore Arosa Climate.