I think I'm adjusting to the dew point in Louisiana. I did 14 miles the other day in 80F air temp, 75F dew point and it didn't feel as bad as it did last year. Granted, I was about 15 lbs heavier this time last year, so I think being in better shape may have made the humid conditions more bearable.
I disagree with the poster who said 50/49 air/dp will leave you drenched in sweat. Maybe if you're naturally sweaty, conditions won't matter much. But I can finish a long run in conditions like that and be almost dry. Except my nether regions. Those always are moist after a run, no matter the humidity or air temp.
The worst my nether regions ever had it was on a 8 mile morning run one winter. I'd gotten used to temps in the low teens and had dressed accordingly. Without checking the weather I dressed as I had been and went out the door. 2 miles later, mini me was throbbing in pain. By the end of the 8 mile run, I was seriously worried about frost bite and permanent damage. Turns out the temps had dropped to less than 5F. I learned that 5F is a 3-layer kind of day for the little guy. I don't know what was more painful, the end of the run or hopping into a warm shower immediately after.
Is Flagpole still around? Haven't heard from that guy in a while. These boards lose people all the time and little peckerwoods are always taking their places. Oh for the good ol' days.