I've been in a dry sauna as the temperature gradually reached its max peak of 105 C. At that temperature, the trick is to not move so that there's a relatively static layer of air around you. You also have to breathe slowly so as not to burn your nostrils/throat. And you perspire like crazy and the evaporation of your perspiration cools your body. It's still crazy hot though and you can't last very long before having to exit.