Interesting question and a lot of focus on the POH...
I'm no stranger to GA in hot climates, but perhaps the question some should be asking is "how long can my human body perform in 40+ degree temperatures without a whiff of air conditioning in a c172". I've done some fairly stupid things when I've been hot and dehydrated, and when that door shuts and the sweat starts dripping, don't expect your mental capacity to be at an all time high.