I went to Australia in July about ten years ago. It wasn’t too cold.
It’s been an unusually warm July here too this year (funny that). I’m dreading summer after seeing what’s been going on in the northern hemisphere.
I knew Sydney winters were mild compared to a place like Chicago but I still packed a few warm hoodies thinking it would be chilly. I definitely didn’t need them except a few nights when the temperature actually did drop.
Loved the city and surrounding areas we visited but if that’s your winter, I’m not sure I’d survive a summer visit.