dragonfly,

I live in SW Texas so I can tell you that by mid May or the beginning of May I will start riding earlier and earlier in the morning to get used to the heat. The stinky hot humid begins in June and goes through August. In those months I hit the road very early 6:30-7:00 AM and am absolutely off by 11:00 after which I go hibernate in the AC for the rest of the day. The heat is bearable only if you ride into it in the spring and then accept that you are going to be stinky hot and dripping for most of your ride, and that you will leave sweat circles on the garage floor when you dismount and walk into the house. I usually keep a beach towel on the bike rack so I can wipe down enough so as not to drip on the rug. Of course then the trick is to get out of the wet clothes and into the cool shower before you start chilling from the ac. How hot is it? Fully frozen insulated bottles are thawed within two hours and tepid by three. I tend to ride in an ranch area that has a lot of small stores and gas stations so I make frequent AC breaks and buy cold water which helps. It is doable but definitely not the best riding conditions. The good thing in the summer is that out on the plains there is usually enough breeze to help cool a little.