Here's old thread of mine about carrying water...
http://forums.teamestrogen.com/showt...ighlight=water
REI has these things on sale...
http://www.rei.com/product/795871
http://www.rei.com/product/799552
I also own this (comes also in seat post clamp if not carbon post)...
http://www.rei.com/product/768770
The way I can carry two full size water bottle on my smaller frame 49cm road bike is with side loader cages... awesome...
http://www.arundelbike.com/Sideloader.html
I can't stand to drink anything flavored, so Cliff Shot Blocks work great for me... like gummi bears, yummy way to get lytes... margarita flavor has x 3 sodium...
http://www.clifbar.com/food/products_shot_bloks/
Last... if you try to plan your route with a gas station for stops to buy some more water that helps too.
My asthma action plan w/my doc is use albuterol inhailer 15mins prior... plus bunch other stuff... and I'm with IndySteele... nights are the hottest imo.... midwest girl here too, btw... ugh on our humidity!