Keeping well hydrated is important when riding in the heat since often you will sweat a lot, and even more so when you factor in the high humidity that goes along with summers in the south. It's been pretty hot and humid in the Northeast as well which is why I prefer to ride very early in the morning; commuting to work isn't much of an option because once it gets over 90 and it's humid I need a shower which I don't have at work.