We live in central NC and I'm very familiar with hot, humid summers. We have a gazebo over our tub and in the warm months we put up a hose in the corner with a misting attachment. It really helps, especially if you are under the mist, but it also lowers the air temp all around the tub. We keep the water as cool as possible, and the shade from the gazebo helps some. I also keep 2-liter pop bottles filled with water and in the freezer and sometimes if we want to soak for a long time on a Friday/Sat evening, I toss the frozen bottles in the tub, about 5 of them. They lower the temp a bit and it cools you when you touch them.
