Chamonix in September

September weather, activities, events & insider tips

September Weather in Chamonix

18°C (64°F) High Temp

5°C (41°F) Low Temp

95mm (3.7 inches) Rainfall

65% Humidity

Is September Right for You?

Advantages

Perfect hiking weather with comfortable 15-18°C (59-64°F) daytime temperatures and crystal-clear mountain views after rain clears
Autumn colors peak in late September - larches turn brilliant gold creating the most photographed season in the Alps
Shoulder season pricing means 30-40% savings on accommodation compared to July-August peak rates
Stable weather patterns with predictable morning clear skies before afternoon cloud buildup - ideal for early alpine starts

Considerations

Mountain refuges and high-altitude cable cars begin closing after September 15th, limiting access to some classic routes
Daylight hours shrink rapidly from 13 hours early September to 11.5 hours by month's end - affecting afternoon activity time
First snowfall typically arrives late September above 2,500m (8,200ft), potentially closing high mountain passes with little warning

Best Activities in September

Tour du Mont Blanc Day Hiking Sections

September offers ideal conditions for tackling sections of this iconic 170km (106-mile) circuit. Cool temperatures prevent overheating on steep ascents, while autumn larches create spectacular golden backdrops. Morning starts at 7am capitalize on stable weather before afternoon clouds roll in around 2pm.

Booking Tip: Book guided day sections 2-3 weeks ahead (typically €45-75 per person for group tours). Look for guides certified by the French Mountain Guide Association. Reference booking widget for current TMB section options.

Aiguille du Midi Cable Car and Alpine Photography

September's crisp air provides exceptional visibility for the 3,842m (12,605ft) ascent. Early morning departures (first car at 8am) offer mirror-calm conditions for photographing the 4,000m+ peaks. The viewing platforms are less crowded than summer peak season.

Booking Tip: Purchase tickets online 5-7 days ahead to guarantee time slots (typically €65-85 return). Weather can change rapidly at altitude - check conditions before ascending. See current ticket options in booking section below.

Chamonix Valley Trail Running Routes

Cool September temperatures create perfect conditions for alpine trail running. The Petit Balcon Sud offers 23km (14.3 miles) of runnable terrain with 800m (2,625ft) elevation gain. Local runners start early to avoid afternoon weather changes and enjoy optimal grip on less muddy trails.

Booking Tip: Join guided trail running groups through local running clubs (typically €25-40 per session). Rent trail running gear locally for €15-25/day. Check current trail running tour options below.

Mer de Glace Glacier Train and Ice Cave Exploration

September's moderate temperatures make the 20-minute cog railway journey comfortable while providing dramatic views of France's largest glacier. The ice cave remains accessible through September before winter closure. Cooler weather means less glacial melt and more stable ice formations.

Booking Tip: Combine train and ice cave tickets for better value (typically €35-45 total). Afternoon visits after 2pm often less crowded. The train operates until late September - verify current schedules in booking widget.

Alpine Mountaineering Skills Courses

September offers ideal learning conditions for glacier travel and basic mountaineering techniques. Snow is more predictable above 3,000m (9,840ft), and cooler temperatures allow longer practice sessions. Perfect preparation season before winter mountaineering.

Booking Tip: Book internationally certified guide services 3-4 weeks ahead (typically €280-380 per day for private instruction). Look for IFMGA certified guides. Multi-day courses offer better value. See current mountaineering course options below.

Chamonix Valley Cycling Tours

September's comfortable cycling temperatures and reduced summer traffic make valley floor routes ideal for exploring. The Arve Valley cycle path connects Chamonix to Argentière covering 15km (9.3 miles) with minimal elevation gain. Perfect for e-bike tours with mountain backdrops.

Booking Tip: E-bike rentals cost €35-55/day with guided tours at €65-95 per person. Book 1-2 weeks ahead during peak autumn color season. Look for tours that include valley viewpoints and local farm stops. Check current cycling tour options in booking section.

September Events & Festivals

Early September

Fête des Guides (Guide Festival)

Annual celebration honoring Chamonix mountain guides with traditional Alpine ceremonies, equipment demonstrations, and rescue technique displays. Local guides showcase historical climbing gear and share stories from classic Alpine routes.

Late September

Marathon du Mont-Blanc

International trail running event featuring multiple distances from 10km to full 42km mountain marathon. Runners from 40+ countries tackle technical Alpine terrain with significant elevation gain. Even non-participants enjoy the festival atmosphere.

Essential Tips

What to Pack

Layered clothing system - temperatures swing from 5°C (41°F) at dawn to 18°C (64°F) afternoon requiring base layer, insulating mid-layer, and shell jacket

Waterproof hiking boots - September trails can be muddy from overnight rain and morning dew, especially above 1,500m (4,920ft)

Lightweight rain jacket and waterproof pants - afternoon showers arrive quickly and temperatures drop 8-10°C (14-18°F) when wet

Warm hat and gloves for early morning starts - essential for sunrise hikes and cable car rides above 2,000m (6,560ft)

SPF 50+ sunscreen and glacier glasses - UV reflection off snow increases significantly above 2,500m (8,200ft) with UV index reaching 8

Headlamp with extra batteries - daylight ends by 7:30pm late September, essential for descent from afternoon activities

Microspikes or light crampons - first snow above 2,800m (9,185ft) can create slippery conditions on metal walkways and rock

Thermos for hot drinks - mountain refuges close mid-September, so carry warm liquids for longer mountain days

Quick-dry synthetic clothing - avoid cotton as humidity reaches 65% and clothes dry slowly in cool mountain air

Lightweight down jacket - temperature drops rapidly after sunset and wind chill is significant on exposed ridges and cable car platforms

Insider Knowledge

Start mountain activities by 7-8am - afternoon cloud buildup begins around 1-2pm and can completely obscure valley views within an hour

Check lift closure schedules carefully - many high-altitude cable cars close permanently after September 15th for annual maintenance and don't reopen until December

Book accommodations on the valley floor rather than altitude - mountain hotels close early in September and valley locations provide easier access to changing weather options

Local guides recommend the 'golden window' from September 10-25 when autumn colors peak but most infrastructure remains open - plan your visit during this optimal period

Avoid These Mistakes

Assuming summer operating hours continue - many mountain railways and cable cars reduce schedules significantly after September 15th with last runs often at 4pm instead of 6pm

Packing only summer hiking gear - September weather can shift to winter conditions above 2,500m (8,200ft) with little warning, requiring proper insulation and waterproofs

Planning high-altitude activities for late in the day - afternoon weather changes happen rapidly in September, making early morning starts essential for summit attempts and glacier access