I found it’s more than just the number, week of 40+ in Melbourne is tough going, Perth you just seem to get on a bit better and the Doctor fixes a lot and 6am road laps of the river were at least possible.
Highest recorded was 46.4c in Melbourne on Black Saturday when the fires went through up north. It was just horrid and hard to do anything apart from sit inside.
must have been getting up to 40c out on Slickrock in Moab, driving around the steering wheel was always hot, bugger all shade around and even after a short walk I had no desire to be out in the sun much more that day.
Most uncomfortable was high 30’s in Brisbane Humidity, after a thunder storm it just got more humid 🙁