Planning for the weather is a good way to make your trip to Saint-Gervais-les-Bains relaxing and enjoyable, especially when you’re splurging. The hottest months are usually July and August, with an average temperature of 15°C, while the coldest months are January and February, with an average of -2°C. Average annual precipitation for Saint-Gervais-les-Bains is 1688 mm.