Rainfall and temperature outlooks

Climate outlook for September to December

Climate outlook overview

  • The fortnight 10 to 23 August is likely to see above average rainfall across most of Australia, although chances are close to average in southern Victoria, much of Tasmania, and the far northern tropics.
  • The outlook for September to November indicates a wetter than average three-month period for most of the eastern half of Australia but drier than average for northern to central WA.
  • Days are likely to be warmer than average during September to November for the northern half of Australia, Tasmania, and southern Victoria. Chances of warmer or cooler than average days and nights are roughly equal across much of the southern half of the mainland.
  • Nights are likely to be warmer than average over most of Australia, but chances of warmer or cooler than average nights are roughly equal across much of south-west WA.
  • The tropical Pacific Ocean is expected to approach La Niña levels over the coming months, while warmer than average waters are likely in much of the central and eastern Indian Ocean. The Pacific influence is strongest in the wetter September to November outlook for eastern Australia.

A wetter August to November for much of Australia

  • The fortnight of 10 to 23 August is likely to be wetter than average for much of Australia, although chances of a wetter or drier than average fortnight are close to equal across the southern half of Victoria, most of Tasmania, and the far northern tropics.
  • The September to November period is likely to be wetter than average across the eastern half of the mainland (greater than 65% chance in most areas), wetter than average in north-eastern Tasmania and drier than average in parts of south-west Tasmania, and also drier than average (greater than 65% chance) over much of northern to central WA.
  • The northern Australian dry season spans May through September. Tropical northern Australia typically has very low rainfall totals during the dry season, and only a small amount of rainfall is needed to exceed the median.

Warmer nights for most of Australia, days warmer in the north but cooler in parts of the south

  • Daytime temperatures for the fortnight 10 to 23 August are likely to be warmer than average for most of the northern tropics, but cooler than average for much of the southern half of Australia. However, chances of warmer or of cooler than average days are close to average in eastern NSW, Victoria, Tasmania, and south-west WA.
  • For 10 to 23 August, nights are likely to be warmer for most of Australia, though chances are close to average in Tasmania and along towards the southern coastline.
  • Days during September to November are likely to be warmer than average for most of northern Australia (greater than 80% chance) and also for Tasmania and southern Victoria (65 to 80% chance). Across the remainder of the southern half of the mainland, chances of warmer or cooler than average days are close to average.
  • Night-time temperatures for September to November are very likely to be warmer than average for most of Australia (greater than 80% chance in most areas), although chances are close to equal for much of south-west WA.

Climate influences

  • The central and eastern tropical Pacific is expected to continue to cool in the coming months. The majority of models anticipate this cooling will reach or exceed the threshold for La Niña by October. A La Niña WATCH is active.
  • Much of the eastern Indian Ocean remains warmer than average, although the Indian Ocean Dipole (IOD) is currently neutral. The Bureau's model suggests a neutral IOD is most likely for the coming months.
  • The Southern Annular Mode (SAM) is currently positive, and is expected to remain positive throughout August. A positive SAM during winter can bring drier conditions to the southern reaches of the country including Tasmania, but wetter in northern NSW and southern Queensland.
  • Australia's temperature and rainfall variability are also influenced by global warming caused by human activities. Australia's climate has warmed by around 1.4 °C since 1910, while southern Australia has seen a reduction of 10–20% in cool season (April–October) rainfall in recent decades.
  • The Bureau's climate model uses the physics of our atmosphere, oceans, ice and land surface combined with millions of observations from satellites and on land and sea. As a result, it incorporates the influence of climate change and natural climate drivers like ENSO, IOD, the MJO, and SAM in its outlooks.

Product code: IDCKOATCO2

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