Humidity plays a huge role in this. In dry climates, it can be 30-40c without too much problem, you just need to hydrate a lot. If it's humid, then even 25c can

Humidity plays a huge role in this. In dry climates, it can be 30-40c without too much problem, you just need to hydrate a lot. If it's humid, then even 25c can be very uncomfortable.