Hi and welcome Salva.
Well, to start with, yes, most of Australia has dark sky due to low population and a huge country.
The cities are probably the same as most cities anywhere, but you don't have to travel far to find reasonably dark sky. About 1 hour.
1 1/2 - 2 hours and you will be in pitch black!
As far as weather goes, that's a different matter.
The climate here is amazing. It can go from a cool 12c to 40c within 48 hours.
In our summer we get a lot of dust, heat haze, and bushfire smoke. But you might enjoy our winters. We rarely get below -6c and the nights are long and dark
I am out in the country, about 1 1/2 hours west of Melbourne, Victoria and it is nice and dark
Because of the way most Australian cities are set up, you can live out in a dark country town and be at work in the city in 1 to 1 1/2 hours by public transport.
Many people spend that time sitting in traffic to get to work and they live in the city!
Ask more questions if you need to so we can help you