100c is too much on nearly every sauna. However, if you track your "performance" in sauna with a timer you're doing something wrong. The whole idea is to go by feel and enjoy, not count seconds. If sauna is hotter than you prefer or if the ventilation is lacking or whatever it's just fine to pop in for a while, cool off at shower/outside/in a lake and take a second round. And a third and fourth and so on. Or just a short visit to get a sweat on and hop in a shower if you just need a quick cleaning. Whatever happens to suit you at the time, but keeping time and having 'strict' minimum time is not a part of sauna experience.
Sauna
Saunaposting
A place to discuss saunas.
So the water was boiling? Does c mean something else in this context?
Air temperature in sauna can be over 100 degrees celsius. That doesn't mean that everything inside the sauna is at the same temperature, like closer to the floor even air temperature is considerably lower.
This!
I'll also add humans don't experience absolute temperature. Humans experience flows of energy. So if you touch a very cold or a very hot highly insulated surface, you don't feel it very much. If you touch a highly conductive surface, that energy flows very quickly and you feel it.
Imagine picking up an ice cold piece of plastic out of the freezer, versus an ice cube, or an ice cold piece of metal like a whiskey rock. They feel colder even though they're All the same temperature