Climate outlook for August to November
Long-range forecast overview
The long-range forecast for August to October shows:
- Rainfall is likely to be within the typical seasonal range for much of Australia, including coastal regions of NSW and Victoria.
- Wetter than average conditions are likely for parts of the south-east, central and far west; and drier than average for much of the tropical north and south-western Tasmania.
- Warmer than average days and nights are likely to very likely across most of Australia; however, periods of cold weather are still possible.
Rainfall—Summary
Above average rainfall likely for parts of south-eastern, central, and far western Australia
May to September is the northern Australian dry season when large areas receive less than 25 mm of rain over the season. During this time, only a small amount of rainfall is needed to exceed the average.
August to October
- Rainfall is likely to be within the typical range for the season for most of Australia, including coastal regions of NSW and Victoria.
- Above average rainfall is likely (60 to 75% chance) for western WA, and parts of central and south-eastern inland Australia. Below average rainfall is likely (60 to 70% chance) for much of the tropical north and south-western Tasmania.
- During August, rainfall is likely (60 to 80% chance) to be above average for much of Australia, except across the northern tropics and parts of south-eastern Australia.
- Compared to last week's issue (25 July), there is an increased chance of above average August rainfall over the northern half of WA, SA, southern Queensland and western NSW. However, for August to October, there is a decreased chance of above average rainfall over most of inland NSW and southern Queensland.
Temperature—Summary
Warmer August to October days and nights likely across most of Australia
August to October
- Above average maximum and minimum temperatures are likely to very likely (60% to greater than 80% chance) across most of Australia; however, being winter, periods of unusually cold weather are still possible.
- There is an increased chance of unusually high maximum temperatures1 for most of Australia, particularly for parts of the north and Tasmania.
- There is an increased chance of unusually high minimum temperatures1 across Australia, particularly in the north, north-east and south-east.
1 Unusually high maximum and minimum temperatures are those in the warmest 20% of August to October 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 physics of the atmosphere, similar to our weather model, but also includes the physics of the oceans. It uses millions of observations from satellites and instruments on land and sea.
We report on global and hemispheric climate indicators that can help understand the sources of longer-term predictability in our forecasts. These factors are mainly associated with interactions between the atmosphere and ocean.
For general information, our monitoring of these climate indicators suggests:
- The El Niño–Southern Oscillation (ENSO) is neutral.
- Sea surface temperatures (SSTs) in the central Pacific Ocean are ENSO-neutral, following a steady cooling from El Niño levels since December 2023. This surface cooling is being sustained by deep waters surfacing in the central and eastern Pacific. Since June, the rate and extent of cooling both at the surface and at depth have slowed. Atmospheric patterns, including cloud and surface pressure, are also ENSO-neutral.
- ENSO is likely to remain neutral until at least early spring. Four of 7 climate models suggest the possibility of SSTs reaching the La Niña threshold (below −0.8 °C) by October, although one of these models only just reaches the threshold. The remaining 3 models maintain ENSO-neutral throughout the forecast period. Compared with earlier forecasts, the potential for La Niña development is now later in spring.
- The ENSO Outlook remains at La Niña Watch. La Niña Watch does not guarantee La Niña development, only that there is about an equal chance of ENSO remaining neutral or La Niña developing later in the year.
- The Indian Ocean Dipole (IOD) is currently neutral. The latest model outlooks indicate that the IOD is likely to remain neutral until at least the end of winter. Three of 5 climate models suggest that during spring, negative IOD development is likely, while 2 suggest IOD will remain neutral.
- Global SSTs have been the warmest on record for each month between April 2023 and June 2024. July 2024 SSTs are comparable with 2023. Both July 2023 and July 2024 are much warmer than any other July on record.
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