Ounces (or mils) in a bottle change depending on what people have, but there's always 60 minutes in an hour. I go off of 25oz because that's what my bottles hold.

Can't get out of the house until late today, but the high will only be ~100º, with humidity in the teens. Probably just 3 bottles for the ~3 hours, but if I get home with the 4th bottle full, better than empty. The tricky part will be the roughly 20 miles of out-in-the-open climbing with no access to services followed by ten miles of flat ground to get to a water refill. Today will be riding at a pace to manage water intake more than anything else