Last updated: February 26, 2025
September in Chamonix-Mont-Blanc, France ushers in the transition from summer warmth to autumn chill, with maximum temperatures reaching 21°C (71°F) and an average of 10°C (49°F). Visitors should prepare for variable conditions, as the minimum temperatures can dip to -8°C (19°F), reminding us of nature's brisk embrace. Expect a total precipitation of 109 mm (4.3 in) over 16 days, contributing to the region's lush landscapes, while the humidity hovers around 73%, adding a refreshing element to the mountain air. Whether you're exploring the vibrant trails or soaking in the stunning vistas, September offers a unique blend of weather that captures the essence of Chamonix's alpine allure.
As September unfolds in Chamonix-Mont-Blanc, the alpine air begins to cool, bringing a refreshing shift from the warmth of summer. With temperatures ranging from a minimum of -8°C (19°F) to a maximum of 21°C (71°F), the month offers a pleasant average of 10°C (49°F), perfect for both adventurous hikers and casual visitors. This transitional month sees a gradual decline from the peak summer heat of July and August, hinting at the impending winter chill, yet still allowing for enjoyable outdoor activities in the stunning surroundings. Embrace the crispness of early autumn while witnessing the enchanting colors of the landscape as nature prepares for the colder months ahead.
In September, Chamonix-Mont-Blanc experiences a noticeable decrease in precipitation, with 109 mm (4.3 in) of rain accumulating over approximately 16 days. This marks a shift from the wetter summer months, particularly May, which sees the highest rainfall at 224 mm. As the season transitions into autumn, the weather becomes more stable, reflected in the reduced precipitation compared to earlier summer patterns. Despite the dip, September still captures the lush essence of the Alps, characterized by crisp air and vibrant fall colors, making it a captivating time for visitors who enjoy the serene beauty of the mountains amidst a milder rainfall.
In September, Chamonix-Mont-Blanc experiences a slight uptick in humidity at 73%, signaling the transition from the drier summer months. This modest increase follows a steady decline from a high of 91% in January to a low of 63% in August, offering a refreshing balance as autumn approaches. While humidity remains lower than many earlier months, September's figures mark a shift towards the wetter conditions characteristic of autumn, leading into the higher humidity levels of October at 89%. Overall, the trend reflects a seasonal rhythm, where warmth gives way to moisture, setting the stage for the stunning autumn landscapes that define this enchanting region.
In September, Chamonix-Mont-Blanc enjoys a high UV Index of 7, signaling that sun exposure should be approached with caution. As summer fades, this is a notable decrease from the peak of very high UV levels experienced in June and July, where burn times shortened to just 15 minutes. Fortunately, visitors can still relish outdoor adventures for up to 25 minutes before the sun's rays become harmful. This trend reflects a gradual easing into autumn, emphasizing the importance of sun protection even during transitional months. For those planning to bask in the stunning Alpine scenery, awareness of these UV levels is vital. To stay informed about the UV Index throughout the year, check out Chamonix-Mont-Blanc UV Index.
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September in Chamonix-Mont-Blanc is a delightful transition from the bustling summer months, basking in a robust 331 hours of sunshine. This idyllic month showcases a gentle decline from the peak of 422 hours in July, while still offering plenty of radiant days to explore the stunning alpine scenery. As the vibrant colors of fall begin to emerge, visitors can enjoy the crisp air and breathtaking views, making it a prime time for hiking and outdoor activities. This gradual decrease in sunlight from summer to autumn is accompanied by a shift in the region's atmosphere, allowing for a serene escape into nature as the warmth of September invites adventure amidst the majestic peaks.
As summer transitions to autumn, September in Chamonix-Mont-Blanc presents a 30% chance of sunny weather. This percentage, while moderate, reflects a notable decline from the peak summer months, where the likelihood hovered between 33% and 37% in July and August. However, September continues to be brighter than the chillier months that follow, such as October, which boasts a 45% chance of sun. Overall, while September may not be the sunniest time of year, it still offers a pleasant balance before the autumnal chill sets in, making it an appealing option for those seeking to experience the beauty of the French Alps.
As summer fades in Chamonix-Mont-Blanc, September marks a significant transition in daylight duration. With 12 hours of daylight, this month showcases a comfortable balance—still generous compared to the winter months. Following the sun-drenched days of July and August, which each offered 15 and 14 hours respectively, September signals the start of a gradual decrease in light. This trend continues into the cooler months, as daylight diminishes to 10 hours in October and even less in the winter. The shift from the peak summer brightness to the subdued light of fall creates a beautiful ambiance in the stunning alpine landscape, inviting both reflection and exploration.
As September arrives in Chamonix-Mont-Blanc, a gentle calm envelops the landscape, with average wind speeds dropping to 1.0 m/s (2 mph). This is the lowest speed recorded for the year, indicating a serene transition from the vibrant summer months into the crispness of autumn. The trend reflects a gradual decline in wind intensity as the seasons shift, moving from the steady breathing of spring and summer towards the quieter embrace of fall. This serene atmosphere enhances the stunning mountain views, making September an enchanting time for visitors and nature enthusiasts alike, where the stillness of the air beautifully complements the stunning alpine scenery.
The weather in Chamonix-Mont-Blanc changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in Chamonix-Mont-Blanc and find detailed weather information for every month.
When comparing September and January weather in Chamonix-Mont-Blanc, notable differences emerge. September boasts milder temperatures, with highs averaging 21°C (71°F) and lows around -8°C (19°F), while January experiences much colder conditions, with temperatures dropping to a minimum of -25°C (-13°F) and an average of -8°C (19°F). Precipitation levels are higher in January, totaling 171 mm (6.7 in) over just 10 days, compared to September's 109 mm (4.3 in) over 16 days, reflecting the shift to more intense winter weather. Additionally, January has a higher humidity level at 91%, contributing to the colder, more subdued atmosphere typical of winter. For more detailed insights, you can check out Chamonix-Mont-Blanc weather in January.
When comparing the weather in September and February, a stark contrast in temperatures and conditions becomes evident. September typically sees milder temperatures, ranging from a chilly -8°C (19°F) at night to a pleasant 21°C (71°F) during the day, with an average temperature of 10°C (49°F). This month also experiences significant precipitation, totaling 109 mm (4.3 in) over 16 days, and a humidity level of 73%. In contrast, February is much colder, with minimum temperatures plummeting to -21°C (-5°F) and daytime highs reaching just 11°C (52°F). The average temperature settles around -4°C (26°F). February also records more precipitation, amounting to 141 mm (5.5 in) over 11 days, alongside a higher humidity level of 87%. For more detailed weather information, you can check Chamonix-Mont-Blanc weather in February.
When comparing the weather in September and March, it's clear that March is significantly colder, with average temperatures around -1°C (31°F), while September enjoys a milder average of 10°C (49°F). March also sees lower minimum temperatures, dipping to -25°C (-12°F), in contrast to September's milder low of -8°C (19°F). Precipitation is higher in March at 175 mm (6.9 in) over 15 days, compared to September's 109 mm (4.3 in) over 16 days, and the humidity is notably higher in March at 84% versus September's 73%. For more detailed information, you can refer to Chamonix-Mont-Blanc weather in March.
When comparing the weather between September and April, September typically offers milder temperatures with a minimum of -8°C (19°F) and an average of 10°C (49°F), peaking at a maximum of 21°C (71°F). In contrast, April tends to be colder, with lows of -16°C (3°F) and an average of just 3°C (38°F), though it can reach a maximum of 17°C (63°F). Precipitation is more frequent in September, occurring over 16 days with a total of 109 mm (4.3 in), while April sees slightly less rain, totaling 84 mm (3.3 in) spread over 13 days. Humidity is also higher in April at 83%, compared to September’s 73%. For a more detailed view of April's climate, you can check Chamonix-Mont-Blanc weather in April.
Comparing the weather in September and May reveals some intriguing contrasts. In September, temperatures range from a minimum of -8°C (19°F) to a maximum of 21°C (71°F), with an average of 10°C (49°F). This month experiences 109 mm (4.3 in) of precipitation over 16 days and has a humidity level of 73%. In contrast, May sees slightly cooler minimum temperatures of -12°C (11°F) but can reach a maximum of 23°C (74°F), with an average temperature of 7°C (45°F). May is also wetter, with a total precipitation of 224 mm (8.8 in) over 21 days and higher humidity at 78%. For more details on May's weather, check Chamonix-Mont-Blanc weather in May.
In comparing the weather of September and June, we notice distinct differences. September experiences a broader temperature range, with minimums dipping to -8°C (19°F) and maximums reaching 21°C (71°F), resulting in a pleasant average of 10°C (49°F). In contrast, June has milder temperatures, with a minimum of -3°C (28°F) and a maximum of 28°C (83°F), yielding an average of 12°C (54°F). Rainfall is more substantial in June, totaling 167 mm (6.6 in) over 20 days compared to September's 109 mm (4.3 in) over 16 days. Humidity levels remain quite similar, hovering around 73% in September and 75% in June. For more detailed insights into June weather in Chamonix-Mont-Blanc, check out Chamonix-Mont-Blanc weather in June.
When comparing the weather in September to that of July, there are notable differences in temperature and precipitation patterns. September experiences cooler temperatures, with a minimum of -8°C (19°F), an average of 10°C (49°F), and a maximum of 21°C (71°F). In contrast, July boasts warmer conditions, featuring a minimum of 2°C (36°F), an average of 14°C (57°F), and a maximum of 27°C (81°F). Precipitation in September totals 109 mm (4.3 in) over 16 days, while July sees a higher total of 162 mm (6.4 in) across 18 days. Humidity levels remain fairly consistent, with September at 73% and July slightly lower at 72%. For a closer look at July's climate, you can visit Chamonix-Mont-Blanc weather in July.
In comparing the weather between August and September, one can observe notable differences in both temperature and precipitation patterns. September experiences cooler temperatures, with a minimum of -8°C (19°F) and a higher average of 10°C (49°F), compared to August's milder minimum of 2°C (36°F) and average of 13°C (56°F). While August enjoys warmer conditions, peaking at 25°C (77°F), September’s maximum is significantly lower at 21°C (71°F). Precipitation is also slightly less in September, totaling 109 mm (4.3 in) over 16 days, versus August's 149 mm (5.9 in) over 17 days. Furthermore, September carries higher humidity levels at 73%, compared to August's 63%. For more specific details on August weather conditions, you can visit Chamonix-Mont-Blanc weather in August.
September and October present a noticeable shift in weather conditions. In September, temperatures range from a minimum of -8°C (19°F) to a maximum of 21°C (71°F), with an average of 10°C (49°F), while October sees a decrease in average temperature to 5°C (42°F) and a max of 18°C (65°F). Precipitation increases in October to 133 mm (5.3 in), occurring over 13 days compared to September's 109 mm (4.3 in) over 16 days. Additionally, the humidity rises from 73% in September to 89% in October, making the air feel significantly more damp. For a detailed overview of October's weather in Chamonix, check out Chamonix-Mont-Blanc weather in October.
September and November present distinct variations in weather conditions. In September, temperatures range from a minimum of -8°C (19°F) to a pleasant average of 10°C (49°F), peaking at a maximum of 21°C (71°F). The month sees around 109 mm (4.3 in) of precipitation over 16 days, with humidity levels averaging 73%. In contrast, November experiences significantly colder temperatures, with a minimum of -18°C (-1°F) and an average temperature of -1°C (30°F), while the maximum can reach 15°C (60°F). The precipitation is slightly higher at 120 mm (4.7 in) across 13 days, along with increased humidity at 90%. For more details, you can check Chamonix-Mont-Blanc weather in November.
September and December present stark contrasts in weather conditions. In September, temperatures range from a minimum of -8°C (19°F) to a comfortable maximum of 21°C (71°F), with an average of 10°C (49°F) and relatively lower precipitation of 109 mm (4.3 in) over 16 days. The humidity level stands at 73%, creating a crisp yet pleasant atmosphere. In contrast, December experiences much colder temperatures, with a minimum of -23°C (-8°F) and an average of -6°C (22°F), peaking at only 8°C (46°F). The month is notably wetter, receiving 295 mm (11.6 in) of precipitation across 19 days, along with a high humidity level of 90%. For a detailed overview of the weather in December, you can visit Chamonix-Mont-Blanc weather in December.
As summer fades into autumn, September in Chamonix-Mont-Blanc brings a refreshing shift in weather that marks a distinct transition from the warmer months. Temperatures start to cool down, presenting a more crisp atmosphere perfect for outdoor adventures, while the occasional rainfall adds a cozy touch to the landscape. With a blend of mild days and chilly nights, September is often characterized by its increased humidity and frequent precipitation, making the lush alpine scenery even more vibrant. As the foliage begins to change, visitors can enjoy a beautiful tapestry of colors, offering a unique backdrop for exploring this enchanting region. For a deeper insight into the seasonal variations, be sure to check out the detailed Chamonix-Mont-Blanc Climate.