the problem with cooler temps is you don't Think you need as much water but you're still losing it by sweating and breathing with your mouth open. Because the temps are cooler and you're wearing fabrics that wick you may not realize just how Much you're sweating. The nicest thing I ever read was: your body will get rid of the excess water if you take in too much! So drink drink drink. I try to drink at least a bottle an hour every season of the year except summer: when I try to drink more.
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"