Hi Sally,
I live in Melbourne, so our winters are more temperate than inland Victoria. We had a daily max. of around 20 degrees C up until just over a week ago; this past week the temperature hasn't gotten above 15-16 deg C and gets down to around 4-5 at night. It's also been raining every day this week, with more rain forecast for the weekend. The temperatures won't drop much more (in regional Victoria and outside Melbourne there are places that will regularly see between -1 and 1 overnight through winter), but it'll remain like that for the next 3-4 months. The summer just gone was a lot more temperate than usual (usually we have a week around 40 deg C, whereas I don't think we even got a single day), so who knows if winter will follow the usual pattern. Melbourne weather is known for its unpredictability, but even these last six months it seems like it's ignoring the forecast a lot more than usual.