The way I see it customers are in control of these things. Whenever you are there you can make it quite high (or low) based on your personal wishes. Of course it's a public place, so you have to pay attention to desires and opinions of others.
I go every Wednesday and the Russian sauna is always very near 120c. I go at open(10a) and it's never terribly crowded.
It's always fuctioning at its best (reaching the highest temperature if desired) in the morning. I prefer visiting on Saturday or Sunday morning to beat the crowd for the best experience.
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