I read up on giving water to breastfed babies last summer. I found this great article from the Australian Breastfeeding Association (hey, what better country to check for advice than one with a really warm climate!)
Extract:
Most parents worry at some stage that their fully-breastfed baby may not be getting enough to drink in hot weather and they ask if they should give boiled water or fruit juice 'just in case'. The answer in most cases is that extra fluids are not required if your baby is breastfed whenever he needs and this may be more often than usual - just as you are drinking more often.
Breastmilk contains a perfectly balanced ratio of food and water to meet all your baby's needs. It is a living fluid, ever-changing to suit your baby and even in response to the weather! The first milk your baby gets from a full breast has a low fat content and naturally quenches baby's thirst. Once the let-down has occurred, the fat content of the milk gradually increases as the breast softens. This later milk has a creamier appearance and satisfies baby's hunger.
In hot weather a thirsty baby may want to breastfeed more frequently but for shorter periods. In this way he is getting more low-fat milk and so is satisfying his thirst. If you need to be away from your baby, it is preferable that he has expressed breastmilk (EBM) or small amounts of cooled, boiled water.
An older baby or toddler who is no longer exclusively breastfed may be encouraged to drink water between breastfeeds. You can also offer extra 'snack' breastfeeds to keep him well hydrated. Another refreshing idea for toddlers is to freeze fruit pieces, such as orange quarters, peeled banana or slices of pineapple - cooling and fun, just be prepared for the very sticky mess!
- Some babies become sleepy travelling in hot weather. You may need to stop and wake your baby for feeds.
- The effect of car airconditioners can cause some dehydration - so extra breastfeeds may be necessary on long trips, even if you are cool.
- Prams that are enclosed are airless and can get very hot. An open-weave bassinette, cradle, layback stroller, baby hammock, cot or portable cot is probably cooler for your baby to sleep in.
http://www.breastfeeding.asn.au/bfinfo/cool.html
