Just as you get more thirsty in the warmer weather so does baby,therefore it is vitally important to ensure baby does not dehydrate during the course of the day.
If you exclusively breastfeed your baby,he will not need any additional water but will need to feed more regularly to stop him from being thirsty.
The composition of breastmilk provides both nutrition and hydration.
Older babies and those bottle fed need additional water during the day. This water should be boiled and cooled. Do not use bottle water unless you’ve boiled it first. Introduce small amounts between normal feeds.