September is, by most measures, the finest month in the French Alps. The summer crowds have gone home with the end of the French school holidays. The mountain huts are still open. The trails are dry and the light is extraordinary — that particular golden quality of early autumn, with the first larches beginning to turn and the sky taking on a deeper blue. Lake temperatures are still warm enough to swim. Prices drop sharply from their August peak. And the mountains themselves feel larger, quieter and more accessible than at any other point in the summer season. If you have flexibility in your travel dates, September is the answer.
⛰️ Key points:
- Weather: warm and settled — often the most stable weather of the summer. Expect 20–24°C in valley towns, cold nights above 2,000 m.
- Lakes: still warm enough to swim (19–22°C) in early September, the best beaches are almost empty on weekdays.
- Hiking: trails are at their finest — dry, well-signed, with exceptional autumn light and the first colours appearing from mid-September.
- Mountain huts: open until late September or early October — the last weeks are the quietest and most atmospheric.
- Prices: accommodation drops 20–40% from August levels. September is an excellent month to access hotels that are fully booked in summer.
- Autumn colours: the larches — the only deciduous conifer in the Alps — begin turning gold from mid-September, reaching their peak in early October.
Weather in the French Alps in September
September is statistically one of the most stable months of the year in the Alps. The convective thunderstorms of July and August — which can build rapidly in the afternoon — become less frequent and less violent. Clear morning skies, warm afternoons and the long golden light of autumn evenings are the norm rather than the exception. Valley towns reach 20–24°C regularly; at 1,500 m expect around 16–18°C in the afternoon. Above 2,500 m, nights can drop to 2–5°C and the first September snowfalls at altitude are common from mid-month — these are brief and melt quickly, but serve as a reminder that winter is approaching.
For the Southern Alps (Hautes-Alpes, Haute-Provence), September is genuinely excellent — Briançon, Embrun and the Barcelonnette area retain their exceptional sunshine levels (260–280 hours in September) while the worst summer heat has passed. If weather reliability is your priority, the Southern Alps in September is one of the safest bets in France.
Hiking in September — the best month of the year
September is without question the finest hiking month in the French Alps. The trails are dry and well-compacted after summer use. The flowers of June and July have given way to bilberries, gentians and the first yellowing grasses. The mountain refuges are open but nearly empty — you can book a hut on a multi-day route that was impossible to get into in August. And the light: the low September sun at altitude gives the landscape a quality that photographers spend the whole summer waiting for.
Multi-day routes in September
The great alpine routes — the Tour du Mont Blanc (TMB), the GR5 through the Vanoise, the Tour des Écrins — are at their most enjoyable in September. The TMB in particular is dramatically quieter than in August, when huts are full weeks in advance and the path is crowded. In September, same-week bookings are often possible and the experience feels genuinely wild. The last week of September (before most huts close in early October) is the sweet spot: maximum quiet, maximum colour.
For a shorter multi-day route, the Tour des Bauges (3–4 days, less well-known than the major routes, accessible from Chambéry or Aix-les-Bains) and the Tour du Queyras (5–6 days, Southern Alps, exceptional September sunshine) are outstanding September choices.
Day walks in September
For day walks, the high-altitude terrain (2,000–2,800 m) is at its most accessible in September — snow-free, trails well-maintained after summer, and the afternoon thunderstorm risk significantly lower than in July or August. Excellent destinations for September day walks include the Plateau d’Emparis facing La Meije (Hautes-Alpes), the Hauts Plateaux du Vercors, the Lac Blanc circuit above Chamonix and the Vallon du Clou in the Vanoise — all emptied of summer crowds by mid-September.
For a complete overview of the autumn season in the Alps, see our guide to the French Alps in autumn.
The lakes in September
The Alpine lakes in September are at their best — warm enough to swim (19–22°C at the surface), the beaches almost empty on weekdays, the lakeside restaurants still open and the light exceptional. The lake towns — Annecy, Aix-les-Bains, Évian, Thonon — come back to life as local residents reclaim their own spaces from the August crowds.
Lake Annecy is particularly fine in September: the cycle circuit around the lake (37 km, see our full cycling guide) is at its most pleasant in the cool September morning air, the old town terraces are calmer and the mountain backdrop — with the first snow on the Aravis peaks — is genuinely spectacular. Lac du Bourget and the beaches around Aix-les-Bains are excellent in early September, with water still at 20–22°C and the Revard plateau above taking on its first autumn colours. Lac d’Aiguebelette, with its famously warm water (still 22–24°C in early September) and its “hidden lake” quality, is arguably at its finest in September when the paid beach entry drops or is waived after the high season.
Autumn colours — the larches
The larch (Larix decidua) is the only deciduous conifer in the Alps — and in September and October, when its needles turn from green to vivid gold before falling, it transforms the alpine landscape into something extraordinary. The effect is most dramatic between 1,400 and 2,000 m, where larch forests are densest. The timing varies by altitude and year, but typically:
- Mid-September: first yellowing at highest altitudes (above 1,800 m)
- Late September: peak colour at 1,500–1,800 m — the finest week for larch colour in most years
- Early October: colour descending to lower altitudes, peak in many valley-level forests
The best destinations for larch colour in September and October: the Vallée de Névache (Hautes-Alpes, exceptional larch forests above Briançon), the Col de la Croix de Fer approach roads (Savoie, outstanding gold and red in late September), the Alpe d’Huez forest above Bourg-d’Oisans and the Arêches-Beaufort valley in the Beaufortain.
Mountain villages and towns in September
September is the ideal month to explore the authentic mountain villages — after the August crowds and before the winter season preparation closes some facilities. Villages that are genuinely worth visiting in September include Bonneval-sur-Arc (one of the most beautiful villages in France, at the foot of the Col de l’Iseran, extraordinarily wild), Névache (larch forests, clear river, no ski resort infrastructure), Saint-Véran (highest village in France at 2,042 m, Southern Alps sunshine), Samoëns (Haute-Savoie, botanical garden, farmers’ market) and Pralognan-la-Vanoise (gateway to the Vanoise national park, exceptional September quiet).
The major resort towns — Chamonix, Megève, Courchevel, Val d’Isère — are animated in September as the summer season draws to a close. Chamonix in particular is excellent: the Aiguille du Midi cable car still runs, the Montenvers cog railway accesses the Mer de Glace glacier and the valley is beginning to empty. Hotel prices in Chamonix in September are typically 30–40% lower than in August. See our full Chamonix hotel guide.
Road cycling in September
For road cyclists, September is arguably the finest month in the Alps — the major cols are open, the roads are significantly quieter than in summer and the temperatures are ideal for climbing. Many of the cols reserved for cyclists only (without cars) in summer continue their car-free days into September. The great alpine cycling climbs — Galibier, Alpe d’Huez, Croix de Fer, Madeleine — are all at their most enjoyable when the summer traffic has thinned. The GranFondo events that take place across the Alps in September (Marmotte, Étape du Tour) bring an additional festive dimension for cycling enthusiasts.
Where to stay in the Alps in September
Most resort hotels remain open through September, with rates 20–40% below August. Self-catered apartments are available at very good prices. The key practical note: some facilities in ski resorts begin closing for winter preparation in late September — check that your chosen restaurant, spa or activity is still operating before booking.
Our September recommendations by zone:
- Northern Alps base: Chamonix, Saint-Gervais or Megève for Mont Blanc access and hiking.
- Lake base: Annecy or Aix-les-Bains for lakeside September atmosphere.
- Southern Alps base: Briançon or Serre Chevalier for guaranteed sunshine, larch forests and the Écrins national park.
- Vanoise / Tarentaise: Pralognan-la-Vanoise, Bonneval-sur-Arc or Val d’Isère for high-altitude September hiking and autumn colours.
FAQ — the French Alps in September
September is arguably the finest month to visit the French Alps. The summer crowds have gone, the weather is stable and warm, the trails are in perfect condition, the lakes are still warm enough to swim and the first autumn colours are beginning to appear. Prices are 20–40% below August. For those with flexibility in their travel dates, September is consistently the first choice of experienced alpine travellers.
Yes — in early September, water temperatures in the major Alpine lakes are typically 19–22°C (Annecy, Bourget, Aiguebelette, Léman). Aiguebelette, one of the warmest lakes in France, can reach 23–24°C in early September. By late September, temperatures drop towards 17–18°C — still swimmable for confident swimmers. Most lake beaches in France close their lifeguarded swimming areas after 15 September, so swimming becomes unmonitored after that date.
The larches — the only deciduous conifer in the Alps — begin turning gold from mid-September at high altitude (above 1,800 m), with peak colour at 1,500–1,800 m typically in the last week of September. By early October the colour has descended to lower altitudes. The best destinations for larch colour are the Vallée de Névache above Briançon, the Arêches-Beaufort valley and the approach roads to the Col de la Croix de Fer.
Yes — most mountain huts (refuges) remain open through September, closing in early to mid-October. Late September is the quietest and most atmospheric time to stay in a hut: the summer crowds have gone, booking is easy and the hut keepers are often more relaxed and conversational. The Tour du Mont Blanc, GR5 and other multi-day routes are fully viable in September with hut accommodation.
Layers are essential — warm afternoons at valley level but cold nights at altitude. A waterproof jacket is always needed in the mountains regardless of season. For hiking: warm mid-layer (fleece or light down), waterproof trousers, poles (useful on the trails which can be slippery with morning dew or the first autumn leaves), headlamp for early starts or late descents. For lake and town time: summer clothes for the warmest days, a light jacket for evenings.
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