When it's hot out, I bring 1 bottle with water and 1 with cytomax or gatorade or whatever has electrolytes in it and I like the taste of at the time I use the water to cool off mostly, but try to keep some in reserve to drink if I run out of gatorade. Depending on how far I'm going before I can refill, I'll use the water on my head and neck to cool off if I get too hot.

I'll take heat any day over this dang cold we've been having around here though!