Just get used to drinking warm water. Ive put ice cold water in bidons before and within 10-15 minutes of leaving home on warm mornings (even before the sun is up) the water is warm already. The other thing to do is dribble water from your bidon down through the airvents in your helmet and onto the back of your neck. Instant airconditioning!
Same as Dahondude: First and last response really - get used to drinking warm water. Its not about keeping cool by drinking cool water its about hydration = perspiration = evaporation = cool. But there's also nothing wrong with stopping at the local deli for a cold flat coke, best thing for rehydration and instant energy hit from the vast amounts of sugar in one can.
I use the basic rule - if the ambient temp is above your body temp then you shouldn't really be out there for long periods. Maybe a quick blast in the morning is enough.
Take 2 bottles, refridgerate one and freeze the other!
By the time you're ready to start drinking the 2nd one it's defrosted, cold and ready to go.
Obviously this does require some pre-planning.
Agree - get used to drinking warm, lots of it! If taste's a problem - try rainwater, or a sports drink powder.
The sports drinks work work, because by making water taste better, you drink more of it.
Can you carry 2 bottles on your bike?
Also, I know where, on my routes, I can get water e.g Norton (drinking fountain), Mt Lofty Summit (cafe wil always fill), Meadows (delis and service station, they always have taps). I also know where there isnt any to be had, so I need to be careful - e.g nowhere between Strathalbyn and Goolwa.
On top of the sports drink powder thing - try to get a flavour that you think tastes OK warm. Warm orange flavour makes me want to hurl, but I've found a watermelon flavour sports drink that is just as nice when warm.
Re insulated bottles, remember that the insulation layer results in a bottle that holds less water. :-) I bought one but promptly ditched it in favour of carrying more water.
Sports Medicine SA have a fact sheet about hot weather - mainly for usual sports - but same considerations apply to cycling.
Yhe easy way to keep your water cold is to place the biddon in an old sock that has been soaked in water. Just a few dribbles of water every hour or so will keep it damp. Works well even in forty degrees. Used this trick when touring when there is no fridge available to freeze the second bottle.
If you dont want to use a sock, a white waterbottle will stay cooler than a black or dark coloured one as it absorbs less heat
I freeze the water. For a long ride, I take 2 bottles. Depending on how hot it is, I might freeze a half full bottle and top it up with cold water before leaving home. They certainly don't take long to thaw and I agree about using white bottles. Great idea about the wet sock, I'll give it a try
there are a couple brands of zero (or low) calorie hydration tabs around. I use the High5 Zero tabs. Pop one into your bidon of water to get all your electrolytes without the carbs (or a lot of carbs).
Obviously you also need carbohydrates, but you probably don't want multiple bottles of sugar laden sports drink. Personal choice I guess, but real foods would suit most rides.
Drink regularly a little and often works best.
Unless you are an elite athlete water is as good as any thing you should be having a pee every few hours and it should be a pale colour.
This assumes you have normal kidney function.
The first few hot days of summer can be a shock for many people if a 750 ml bottle lasts more than an hour you may be getting dehydrated in hot weather.
The problem with chilled water is that once it hits your stomach your body expends energy to warm it which only increases the rate of dehydration. Drinking a litre of water before you start your ride is a good idea and if you're going long distances make sure you stop at every opportunity to refill even to the point of diverting off your main route. I got caught out riding from Adelaide to Murray Bridge when I ran short of water after Palmer, theres no obvious water points by the road side so next time I shall go off route to find one. If you know you're going into no mans land carrying an empty bidon in your back pocket for the beginning of the ride and filling up after you've climbed the hills. You might consider carrying a Camel Back on extra long country rides, better a sweaty back than dehydration.
@ Clive, hell Palmer has a big water pipe in it that goes all the way to MB, did you not see it?