France generally has cool winters and mild summers except along the Mediterranean where mild winters and hot summers are more common. With the average winter temperatures ranging between 32-46°F and the average summer temperatures ranging between 61-75°F, you'll find the hotter temperatures in the south. June, July, August, and September have the most favourable weather conditions for the Tour du Mont Blanc, it will be hot in the valleys and temperatures will be between 68°F and 86°F though these can drop to 50°F at night.