Ds was born mid dec and he lived in nappies and singlets. Most days i put a sleeveless and body suit (snap crotch thingy) on over the singlet. At night we wore the same with a muslin wrap and socks. We had the fan on in the room and the a/c going in the house most of the time.
Put it this way, you dont need much. I do remember having a couple of longer all in ones JIC and i did need to use them as we did have a few cooler days over christmas
I have had 2 summer bubs and mine lived in short all in ones suits, singlets and shorts/skirts. I avoided dresses because they ride up and are a PIA for newborns. You'll need heaps of large muslin wraps. For night my girls had a short all in one with light pants and were wrapped in a muslin wrap or slightly heavier cotton wrap. Or you could get a some very light long all in ones for night time too.
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