The BOM prediction follows a summer that is on track to be Australia's third-warmest on record.
In autumn, there is a 60-75 per cent chance of below median rainfall for most of New South Wales (excluding some eastern areas), most of Victoria (excluding east Gippsland), most of Queensland and parts of South Australia, including the southeast, east and northeastern border districts.
The same 60-75 per cent chance of below medium rainfall applies to the south-west corner of Western Australia and large parts of the north of WA.
There is a roughly equal chance of above or below median rainfall for most parts of eastern New South Wales, east Gippsland, most areas of South Australia and most of and southern and central WA.
The BOM says it is important to understand that weather forecasts, especially long-range ones, are probabilistic in nature and always carry a certain degree of uncertainty.
The BOM's long-range forecast can be viewed here: https://bit.ly/3wy9RWG