Tour du Mont Blanc temperature changes
The main window for doing the Tour du Mont Blanc is June to September, because the weather is warm and sunny. Outside these periods, it is colder and the mountain passes are usually laden with snow and and so impassable unless on skis or snow shoes.
Occasionally June can remain cool and, after a heavy winter, it is not uncommon for snow to remain on the passes up to late June. Often this snow is hard from melting and re-freezing and so can become very icy. Although there will be a path trodden through the snow it is best to take walking poles for balance. Some trekkers also take walking crampons.
Average temperatures on the Tour du Mont Blanc
From late June to the end of August it will be hot in the valleys and temperatures will be between 20°C and 30°C but these can drop to 10°C at night. At higher elevations the temperature will become cooler and this can be exacerbated by cool winds. Occasional cold fronts will bring cold, wet weather: you can expect significant temperature drops and difficult conditions in the mountains. It is not uncommon to have snow at the highest passes on the Tour du Mont Blanc during a cold front even in August. Come prepared for all weathers!
Dressing for Tour du Mont Blanc
The best advice is to come prepared for all weather. You should expect it to be hot and need shorts and T shirts. Late afternoon thunder storms will bring heavy rain and thunder storms after a hot day: this makes it a bit cooler, but you need to have good waterproofs. If hit by a cold front, the temperatures will drop dramatically and you will need warm clothes, gloves, wooly hat and gaiters.
There are reliable weather forecasts available so that you can plan what you carry:
We stay at good quality, family-run hotels. We do not stay at mountain huts. All our hotels have areas where you can dry your gear if you have had a wet day.