As people have mentioned, lots of variables and "running" can mean a wide variety of exertion levels and duration.
However, what I will add is that in my experience wind direction is an overlooked factor in overheating. One of the worst runs I can recall heat-wise was far from the hottest in absolute terms (both heat and humidity), but it was an early summer day with high humidity and temperatures in the mid-80s. I ran an out-and-back, with the first 4 miles into a slight headwind. No problem at all in the first four miles. However, on the way back it felt like I was running in dead air, and each mile felt more draining than the entire first half. I stopped to rest in the shade twice on the way back, which is probably the thing that protected me from prolonged negative effects.
I have gone for a 5 mile run in 100 degree weather and humid conditions, and I think only the hottest of those days (maybe 103?) rivaled the un-acclimated death march with a tailwind in mid-80s.