I recommend keeping it though, someone you meet on the trail might need it. I m not sure on the exact amount. A 100 ounce bladder hydration pack is probably enough up to an eight mile hike in the 65-85 degree range. Get hydrated before the hike. It really makes a difference.
Water is the way to go.
Alcohol and caffeine drinks will only make things worse. Most importantly drink it. Even when it s cool outside your body uses water. Click here for the Hydration Articles on HikeArizona. Probably not too much to worry about on hike under 2-3 miles.