One of my friends does Jiu Jitsu. No idea what style though. As he puts it, Jiu Jitsu puts a lot more impact on your body, but capoeira does a lot more cardio. I don't really know anything about Tae Kwon Do that I haven't seen in the movies, which means I know nothing.
115 degrees and 75% humidity? The worst I can remember is 110 in ~80-85%. That's in Louisiana. I could be forgeting worse days, but I'm not usually forced to work in them. Where the hell (literally) do you get those stats?