[wongarsu]

Finnish saunas regularly go to 100°C (210F). I can personally attest that fifteen minutes in dry 100°C air is very survivable, you just get sweaty. Meanwhile 100°C water burns you almost instantly.

Though it's worth noting that when talking about humans in air the humidity plays a huge role. Sweat cools your body through evaporative cooling, which works better the drier the air is. At 100% relative humidity you can't cool down and eventually overheat, at 10% humidity we can survive some ridiculous temperatures for as long as we can keep sweating.

[rapnie]

Yes, some sauna's need you to wear the key of your dressing locker on an arm bracelet. While relaxing nicely in the heat you can instantly burn yourself severely the moment the iron part of the key presses into your skin. (Talking from experience here)