Above average rainfall for most of mainland Australia
The Bureau of Meteorology’s August to October 2025 long-range forecast tips above average rainfall for most of mainland Australia.
The Bureau says above average rainfall is likely to very likely (60% to greater than 80% chance) for most of mainland Australia, apart from the west and far south-east.
It adds that there is an increased chance of unusually high rainfall1, with chances exceeding 50% (5 times the normal likelihood) for southern Queensland, southern Northern Territory, parts of eastern South Australia and western and northern New South Wales, west of the Great Dividing Range.
August and September are within the northern Australian dry season. During this time, most of tropical northern Australia typically receives very low rainfall, with monthly average rainfall less than 10 mm for these months.
During September to November, northern Australia transitions from the dry to the wet season, which is associated with a seasonal increase in humidity, storms and showers.
There is a weak forecast signal for most of western and northern Western Australia, southern Victoria and across Tasmania, including areas affected by prolonged dry conditions. The absence of a strong signal means there is a roughly equal chance of above, below or near-average rainfall, with no strong indication of unusually wet or dry conditions.
1 Unusually high rainfall is in the highest 20% of August to October rainfall, between 1981 and 2018.
North: Increased chance of an earlier onset in the east; later in the west
The Bureau says the northern rainfall onset for the 2025–26 season is likely to be earlier than normal for most of Queensland and the Northern Territory. It’s likely to be later than usual for much of the west.
Across most of Queensland and the Northern Territory, the onset is likely (60–80% chance) to be earlier than normal.
In much of the north and north-west of Western Australia, there is a 60–70% chance of later than normal onset.
Areas around the northern part of the Western Australia–Northern Territory border have roughly equal chances of an earlier, later or near-normal onset.
Since the last edition on 17 July, the chance of an earlier than normal onset has increased slightly over much of Queensland and the Northern Territory. The chance of a later onset in the west has decreased slightly.
Source: Bureau of Meteorology