My vote goes to Charleston. The 2 years I was stationed there, the average heat index in the summer had to be in the 105-110 degree range. I think it's worse than Tampa, were I live now.
But I think the dampest place I've ever been had to be Baton Rouge in late July. Ick.....
YOu got that right. I vividly remember having to change a tire inside a shady parking garage in early April in Charleston, and being drenched with sweat almost immediately. I think you could draw a triangle, from Augusta, GA, to Columbia, to Charleston, and have the steamiest place this side of Burma.
My sister just finished a 3-year job in Doha, Qatar. The summer temperatures there hover around 115-120 (that's just dry air temperature), and they're right on the Persian Gulf, so it's humid, too. Don't know of anywhere hotter thatn that.