That's like the coolest and worst thing to witness. Like "Ooo, evaporation! Scienc-" but then it's turns into the soggy buttcrack of Florida in the span of in a few minutes when the ambient air temperature and the sun takes it to the logical conclusion. Or as my parents call it "Hong Kong". In cases where I encountered those or similar days, I had AC somewhere so it wasn't too bad. Also 34°C is about 93°F which is just about when things get shitty. You don't need 100°+F to be shitty. If it is humid though, the temperature needed to be shitty is lower. I'd argue that you can put it in the upper 80°F for the start because:
With higher temperature, the quicker it saps you of energy. With dry heat, you can kind of still work even at 110°F. It's an oven but you'd be fine and be downing water (with a salt source) like crazy.