Chamonix-Mont-Blanc Weather in September
During September, Chamonix-Mont-Blanc experiences moderate daytime temperatures of 14°C (57°F) and cooler nights around 3°C (37°F). Expect quite a bit of rainfall. Around 120 mm (4.7 in) is typical.
Rainfall in Chamonix-Mont-Blanc in September
The climate data from previous years indicates about 15 days of rain, averaging 120 mm (4.7 in) for the month. Individual showers can be quite heavy this month. A proper umbrella or rain jacket is worth having.
Temperature in Chamonix-Mont-Blanc in September
In September, Chamonix-Mont-Blanc gets moderate temperatures, with highs of 14°C (57°F). Nights cool to around 3°C (37°F). Conditions are often most pleasant around the middle of the day. With overnight lows of 3°C (37°F), nights are cold. The cold air does make for deep, comfortable sleep if you have enough blankets.
Sunshine in Chamonix-Mont-Blanc in September
Expect sunny days throughout the month, with an estimated 190 hours of sunshine. Despite the cool temperatures, the sunny skies make it a pleasant time to visit Chamonix-Mont-Blanc.For Chamonix-Mont-Blanc itself, July and August generally stand out with the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit France, check out our Chamonix-Mont-Blanc's climate page.
Chamonix-Mont-Blanc Temperature in September
Min Temperature
3°C (37°F)
Max Temperature
14°C (57°F)
Chance of Rain
49%
Precipitation
120 mm (4.7 in)
Rainy days
15 days
Sunshine
190 hours
Percentage Sunshine
Daily Historical Temperatures
50-year average (1976-2025)
Based on our historical records, temperatures in Chamonix-Mont-Blanc typically drop from around 20°C (68°F) at the start of September to approximately 16°C (61°F) by the end. Nights are cold, with lows typically ranging from 6°C (43°F) to 9°C (48°F).
Average temperatures in September
Daily Historical Precipitation
50-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for Chamonix-Mont-Blanc in September
Browse day-by-day weather records for Chamonix-Mont-Blanc spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Chamonix-Mont-Blanc historical weather extremes in September
According to our 49 years of weather records for Chamonix-Mont-Blanc, the following extremes were recorded between 1976 and 2025.
- On September 13, 1987, temperatures climbed to 30°C (86°F), marking the warmest September day on record.
- On September 25, 2002, Chamonix-Mont-Blanc saw its coldest September day with temperatures maxing out at 1°C (34°F).
- Chamonix-Mont-Blanc registered its coldest September night on September 5, 1992, with temperatures dropping to -2°C (28°F).
- Peak precipitation in September occurred on September 1, 2012, when 52 mm (2 in) of precipitation was measured.
Best Places in France in September
Find out more about the weather in France and which places have the best travel conditions in this month. See all of France in September →
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What to Wear in Chamonix-Mont-Blanc in September
Pack for changing conditions in Chamonix-Mont-Blanc in September. Bring a mix of short and long sleeves, a warm layer like a hoodie or light jacket, and comfortable pants. The key is being able to add or remove layers as the days goes by. Prepare for significant rainfall with proper waterproof clothing and shoes. You'll definitely want to pack sunglasses and sunscreen. There will be plenty of bright sunshine this month.What To Do in Chamonix-Mont-Blanc in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit France, check out our Chamonix-Mont-Blanc's climate page.
See the full Chamonix-Mont-Blanc climate overview or explore weather in France.
