Sydney, Melbourne, Brisbane weather: Polar blast sends temperatures plunging

Australians are in for a chilly week, with the mercury set to plunge to record lows for multiple capital cities.

Sydneysiders have shivered through back-to-back chilly mornings, as a cold front moves across the eastern third of the country, bringing icy mornings and even colder nights.

And there's little reprieve in sight, with meteorologists warning that Wednesday was expected to be the coldest morning of the year so far for those in Sydney and Melbourne.

'We are in the midst of a cold outbreak this week but it is more keenly felt in the night, daytime temperatures are pretty close to average for June,' Sky News Weather meteorologist Alison Osborne said.

'We have quite a cold southerly wind over the eastern third of the country, it's pretty cloud-free as well.

'This time of year, when you have a clear sky overnight it generally translates to very cold conditions in the morning because the heat escapes very quickly.'

Sydneysiders will have to rug up as the Harbour City shivers through a low of just five degrees on Wednesday.

'For Sydneysiders, there will be lovely winter sunshine Tuesday and Wednesday afternoon,' Ms Osbourne said.

'It's almost like the price we pay for our beautiful winter afternoons is we do get those bitterly cold mornings.'

Those living in the nation's capital are also looking at some freezing conditions this week, with Canberra to be as cold as -1C on Tuesday and -3C on Wednesday.

On Thursday, Melbourne will reach a top of just 12C with rain forecast, while Adelaide will have a maximum of 15C with rain also predicted.  

Canberra will reach a top of 13C this weekend.

Brisbane will also see some chilly mornings, although temperatures are set to linger around the low 20s in the daytimes.

The Queensland capital will see a low of 8C on Tuesday. 

Further south in Tasmania, Hobart will see its warmest day on Thursday with a top of 17C. Minimum temperatures will linger around 4C and 5C throughout the week. 

Perth will be dry and sunny with maximum temperatures to linger in the high teens.

The WA capital's coldest day will be on Thursday with a minimum of 7C forecast.

Darwin will meanwhile escape the cold weather with temperatures remaining in the low 30s. Minimum conditions will see some mornings drop to 17C.