106F here in Atlanta. I don't know what the index was, but the humidity down here makes that a whole lot hotter than the same thing out west. But I don't mind the heat. I like it so much better than the cold. I'm not too modest to lose most of my clothes. As long as I can keep plenty of water moving thru me I'm fine. But on all day rides I'll most definitely slow down. I can't keep hydrated regardless of how much I drink, past a certain point. I'll have belly full of water and need more.