NOLA is humid!!!!! I used to visit there in the summer, and I swear, you can drink the air! its sweltering. I guess you can get used to it, but when you come from the NE and then go to NOLA, holy cow! its a transition.
1. stay hydrated.
2. seek shade
3. wear a hat! the sun will rip the hide off of you
4. avoid alcohol. it makes it worse
Enjoy your trip!