Taking the local weather in Gilly-sur-Isère into account can help you maximise your time at the pool during your trip. 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 -1°C. The snowiest months in Gilly-sur-Isère are October, September, May and December, with each month seeing an average of 14 cm of snowfall.