I dove dry two days this past weekend. My new 100 gram (versus the prior 200 gram) Thinsulate thermals made it much more tolerable in the 95 degree air and piercing Florida sun. It was hot, but after I rinsed off with the boat's hose, and then when I entered the the 85 degree surface water, I felt much better.. . . I'm still not keen on overheating before the dive (sorry SDM!). It was enough to try the suit on in the diveshop and have sweat rolling off of me because it was such a hot day!
On the bottom, it was 75. All the wetsuit divers were cutting their dives short. After they ascended, my buddy and I had the whole wreck to ourselves for about twenty minutes.
Hmmm. I changed my mind. Everyone, keep diving wet. Don't get a drysuit!