This was my reaction, too. Anecdotally, I used to bike in a hot and humid environment. My first century ride (100+ miles in one sitting) was on a day that hit a

This was my reaction, too. Anecdotally, I used to bike in a hot and humid environment. My first century ride (100+ miles in one sitting) was on a day that hit above 100 degrees with at least 80% humidity. I was able to train like that, 3-6 hours in the sun, more or less every day of the summer in similar conditions.