Climate outlook for September to December

Long-range forecast overview

The long-range forecast for September to November shows:

• Rainfall is likely to be above average for most of the eastern two-thirds of Australia, and below average for western parts of the country.
• Warmer than average days are likely across northern, western and south-eastern Australia, with an increased chance of unusually high daytime temperatures in the far north and across Tasmania.
• Warmer than average nights are likely to very likely across Australia, with an increased chance of unusually high overnight temperatures for northern, eastern and central Australia.

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Rainfall—Summary

Above average rainfall likely for eastern two-thirds of Australia

September to November

• Above average rainfall is likely to very likely (60% to greater than 80% chance) for most of the eastern two-thirds of Australia.
• There is an increased chance of unusually high rainfall¹ for scattered areas of eastern Queensland, New South Wales, south-east South Australia, and northern Victoria.
• 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.
• Below average rainfall is likely (60% to 80% chance) for western parts of Western Australia, and south-western Tasmania.

¹Unusually high rainfall is in the highest 20% of September to November rainfall, between 1981 and 2018.

Temperature—Summary

Warmer than average days likely in the north, west and south-east, warmer than average nights likely almost nationwide

September to November

• Above average maximum temperatures are likely to very likely (60% to greater than 80% chance) for most of northern, western and south-eastern Australia.
• There is a weak forecast signal for maximum temperatures for most remaining areas. Enhanced cloud cover related to the forecast for above average rainfall is likely moderating the temperature forecast in locations with a lower chance of above average daytime temperatures.
• There is an increased chance of unusually high maximum temperatures² for parts of far northern Australia and across Tasmania.
• Above average minimum temperatures are likely to very likely (60% to greater than 80% chance) across almost all of Australia.
• There is an increased chance of unusually high minimum temperatures² across most of the country, apart from central and southern Western Australia. 

²Unusually high maximum and minimum temperatures are those in the warmest 20% of September to November days and nights, respectively, between 1981 and 2018.

We generate forecasts for up to 4 months ahead using our long-range forecast model, ACCESS-S. The model simulates the evolution in the state of the atmosphere and oceans for coming months. It uses millions of observations from satellites and instruments on land and at sea.

We monitor global and hemispheric climate indicators that can support our understanding of longer-term predictability of the weather. These indicators are mainly associated with interactions between the atmosphere and ocean.

For general information, our monitoring of these climate indicators shows:

• Sea surface temperatures (SSTs) in the Australian region during July 2025 were +0.56 °C above the 1991–2020 average, the warmest July on record since observations began in 1900. SSTs since July 2024 have been the warmest or second warmest on record for each respective month. Similarly, global SSTs remain substantially above average, with July 2025 the third warmest July on record.
• The sea surface temperatures (SST) analysis for the week ending 3 August 2025 shows warmer than average waters are present across much of the northern Australian region including the Coral Sea, with cooler than average coastal waters off north-west Western Australia. Waters surrounding much of south-east and south-west Australia are also warmer than average.
• Forecasts for the next 3 months show SSTs around Australia are likely to remain warmer than average to the north, east, and south-east, with waters near to slightly above average surrounding much of Western Australia.
• The El Niño–Southern Oscillation (ENSO) remains neutral. The majority of international models assessed, including the Bureau’s, predict ENSO to persist in the neutral phase until at least December. However, several models indicate borderline La Niña conditions in spring and early summer.
• The Indian Ocean Dipole (IOD) is neutral. Most international models predict a shift towards a negative IOD pattern during late winter and early spring. The Bureau's model predicts a shift into the negative IOD range from August to November before returning to neutral IOD values in December.