I play in hot humid conditions (south Pacific) where the cool season is around 25 degrees centigrade and during summer around 30 degrees.
Day before (well, every day really): drink till your pee is clear - that way you know all your cells in the body hold as much water as they can.
During round, I drink 2 big gulps at every tee off. That ends up being 3 liters of water per round. Might get a coke or so halfway if I want some sugar or just something cold.
Personally I think electrolytes drinks are overrated - it's mainly salt loss that makes you feel weak. I bring salted peanuts, crackers, pizza slice or whatever with me. Potato chips good too.
Gatorade has 21 grams of sugar per serving, that's 10 less than a can of coke. If sugar is an issue, leave it. Lots of other chemicals in there too btw:
Lost balls is the killer and that usually happens with the driver.
