I often hear people talking about it being too hot to ride or how they suffered terribly during a hot or humid ride. This really brings home for me how different we all are. Although I am sometimes uncomfortable on an extremely hot day, I have always been able to ride even in temps above 100F with high humidity. I can recall a few times I have completed century rides in 100+ heat.
Yesterday was the hottest day we have had here so far with a high of 101 and heat index over 110. It had dropped a couple of degrees by the time I rode my weekly hilly 30 mile ride at 5:15pm, but it was still plenty hot. I set my personal best time for this course I have been riding for several years.
I know that genetics plays a part in this. I come from generations of people who farmed in South Georgia. I doubt many people without an inherent ability to endure heat and humidity would have stayed here and raised families under these conditions.
But I wonder how much of this comes from acclimation. I do tend to suffer a bit on the first really hot ride every year. But by June I have always done several rides on hot days. I just spent a week riding 60+ miles each day and living outside with highs ranging from 85 at the beginning to 97 on the last couple of days.
I realize that there are people with physical limitations, and I am not ignoring or downplaying that, but I do think that many people "can't" do things in hot weather mostly because they "don't" do things in hot weather.