Well...there's that "much slower" part, too.
I did a couple Centuries this Summer at good speeds with temperatures in the high 80's and low 90's. But that was with only around 3,000' to 4,000' of climbing.
Tomorrow will be at least 95 for a high with a heat index of Summer in Florida and they'll throw around 6,200' of climbing at us. I won't melt, but I will have to work hard to keep the suffering to minimum at the speeds we'll be covering the course at.
Nice video, Zipp! BTW, our secretary just returned from New Bedford. Portuguese biscuits? Who knew!?