We are in Melbourne so at the moment down to 6 ish at night, but even on a 15 degree night izzy will have a s/s jumpsuit, socks, a polar fleecy Bonds jumpsuit, a 2.5 grobag, plus a flannel sheet, a cotton blanket and a polar fleece blanket over the top all tucked in! SOunds like heaps but she is never overheated, but isn't a hot baby generally so we find it works for us. If we used the Grobag recommendations even for 16 degrees (which it was when she was a newborn - we had a heater in her room at 16) she would get cold. I would trial a blanket over him and tuck it all in around him and see how he goes.