Sleepwear for summer

This may sound like a really silly question to ask especially because i have a older kid too but what do you sleep your baby in during summer??
Xavier was a newborn in summer when he was a baby and he was just in a singlet suit because he was such a hot baby and he slept in bed with me. When he got older he would strip himself at night and just sleep in a nappy.
Im trying to buy Alianas clothes for summer now but i have no idea what to get her for bedtime. She will be 6 months at Christmas time when it starts getting really warm.
Would a cotton footed all in one be too hot? or do you just use singlet suits? We live at the top of the south island and it gets pretty hot in the evenings.

Gremlins were 3-4 mths over summer and slept in short sleeved singlet suits with a muslin wrap. The following summer they were 14 or so months and wore short sleeved singlet suits with a summer weight sleep sack.