I'm in Kentucky, so not as far south as you are, but 90+ degree days with humidity indexes almost as high is more the norm than the exception for our river valley summers. One tomato that always keeps going for me even when others just can't is Sioux. I've also grown Super Sioux, but was not nearly as impressive, so the original Sioux is a garden staple at my house. Not only does it thrive in our heat and humidity, it also makes it through the super soggy springs we can have some years. Basically it's just a dependable little work horse for me and one of only two I plant every year without fail. (Commitment is so hard with so many beauties to choose from!) Sure there are others I prefer the flavor of, but Sioux still has plenty of good old fashioned tomato taste I can count on having when others just aren't there to taste at all. I'm no pro... just a backyard gardner who tends to be pretty simple and almost lazy in my growing routines, so if it works for me, odds are it will work for just about anyone. You could try a few if you have the space and see if they do as well for you. Good luck and much abundance in whatever you choose to do.
