After delivering a soggy summer and autumn, La Nina will continue to drench swathes of eastern Australia with above-average rainfall throughout winter.
The Bureau of Meteorology also says there will be at least an 80 per cent chance of warmer than average minimum temperatures for June to August for most of the country.
In its winter outlook released on Thursday, the bureau says the La Nina weather pattern is slowly weakening but most of central and eastern Australia can expect higher than average winter rainfall, only months after devastating floods in northern NSW and southeast Queensland.
Two major weather patterns - the La Nina in the Pacific and the negative Indian Ocean Dipole - along with warmer than average waters around northern Australia are behind the wet winter outlook, the bureau says.
However, parts of southwestern Australia and southwestern Tasmania are likely to have below-average rainfall.
The unusually wet conditions for inland parts of NSW, South Australia, Queensland and the Northern Territory are likely to be in the top 20 per cent of wettest winters.
With already saturated catchments in southeastern Australia, the risk of flooding in these regions remains.
The bureau links Australia's wild temperature and rainfall variability to global warming caused by human activities.
Australia's climate has warmed by nearly 1.5C in the past century.
Southern Australia has seen a reduction of 10 per cent to 20 per cent in cool season (April-October) rainfall in recent decades.
There has also been a trend towards a greater proportion of rain from high-intensity, short-duration events, especially across northern Australia.
That heavy intensity will inevitably lead into flooding, as it did in Lismore earlier this year when the Wilsons River reached a record 14.3 metres.
