I'm in the eastern wheatbelt in W.A. so the temps get rather high, around 40-45 degrees. The thing is it doesn't cool down until mid evening (if at all). I think we have the most number of days over 30 degrees of any place in the southern Australia, fortunately not the humidity to match.
I'm planning to acutally do short sessions this summer as I was dehydrating last summer. Probably just do one lift and a couple of accessories for 15-20mins.