My girls are old enough now for me to keep some cold water in the bath & they go in & out as they please. When they were babies though it was really hard. We were lucky summer before last & had air con. last summer was hard. This year asap I getting a new air con for the house - current one is too old & doesn't work real good. & fixing the one in the car. I am not going through a Dubbo summer pregnant without it. When the girls were little I let them play with cool wet face washers, dummies & teething rings in the fridge - never freeze. lots of water bottles & I got a big plastic box with clear sides from Big W & used it similar to the bath now only I had it in the lounge room. Coz they have high sides there isn't really any worries about water on the carpet. With my youngest I put like a millimetre of water in the bottom & put her in on her belly. Coz the sides are clear you can watch them. They don't need any more than that amount to have fun. She loved it & it was good for tummy time. & at 5 months head control will be pretty good. Or lay him on his back. Obviously keep water very minimal & always watch them, but having her in & out kept her cool. & it was a different experience for her. different to the bath coz she could splash & play by her self.