As in all the eastern part of the Vosges, the climate of Gérardmer is of mountain type, with continental and oceanic influence. If the winters are harsh and snowy, the summers are torrid and can sometimes generate violent thunderstorms. Not far from the city, La roche au diable (the devil's rock) tells how the devil tried to appropriate the stone bearing his name. He would have unleashed a terrible thunderstorm and marked his property with his hand. Napoleon III had it dug to make a road pass through it, and another cavity was discovered inside.