Severe weather warnings are in place for the first day of winter, with warnings of dangerous winds in Australia's east.
Wind gusts of up to 90km/hr are expected in Victoria's Central Districts region, including Melbourne.
The Bureau of Meteorology expects the most damaging winds at about peak hour this morning, before easing around midday.
The recent strong winds have already caused some damage in past days, bringing down trees from Adelaide to Sydney, with one gum tree falling on a house in Armidale in NSW's New England region.
"Be really alert to the potential for falling trees, for debris that come from trees," an SES spokesperson said.
There is also a warning in place for blizzard conditions in Victoria's alpine regions, with predicted wind gusts of up to 100km/hr following a heavy snow day yesterday.
Melbourne is expecting a top of 12C today, but wind chill could make it feel much colder.
In NSW, the SES has responded to about 1400 calls for help since Monday.
Winds of up to 100km/hr have hammered western Sydney suburbs such as Castle Hill, Baulkham Hills and Ryde, as well as Newcastle and the Hunter.
Sydney is expecting a top temperature of 15C, but it's likely to feel like 10C with ongoing icy winds.
Today is expected to be the coldest day of the polar snap, which has seen winds from Antarctica push across South Australia, Victoria, NSW and south-east Queensland, bringing storms, snow and gales.