Rainfall and temperature outlooks

Climate outlook for October to January

Climate outlook overview

  • October to December rainfall is likely to be above median for the eastern two-thirds of Australia, but below median for western Tasmania.
  • Maximum temperatures for October to December are likely to be above median for the far north of Australia extending down western WA, and far south-east Australia. Below median daytime temperatures are more likely for parts of the southern WA coastline, central Australia, and parts of eastern Australia.
  • Above median minimum temperatures for October to December are likely for almost all of Australia, except for parts of southern and northern WA, where the chances of warmer or cooler than median nights are roughly equal.
  • The negative Indian Ocean Dipole has weakened, but the residual pattern in the Indian Ocean typically favours above average rainfall for parts of Australia. The El Niño–Southern Oscillation is neutral, with cooling of the tropical Pacific likely in the coming months. This may also be increasing the chances of above average rainfall for much of eastern and northern Australia.

Wetter end to 2021 for eastern two-thirds of Australia

  • Rainfall for October to December is likely to be above median for the far south coast of WA, the NT, SA, Queensland, NSW, Victoria and eastern Tasmania (chance of exceeding median is greater than 60%). Much of south-east mainland extending up to southern Queensland and into central Australia shows a greater than 80% chance of above median rainfall. Conversely, western Tasmania is likely to have below median rainfall (chance of exceeding the median is less than 40%).
  • The pattern for the months of October and November is similar to the three-month outlook, though the likelihood of exceeding the median rainfall for the eastern two-thirds of Australia is higher in October, and lower in November.
  • Rainfall for November to January also shows a similar pattern to October to December, although chances of exceeding the median are lower.
  • Past accuracy for October to December rainfall is high to very high for most of northern and eastern Australia, extending into SA, with moderate accuracy for western and southern parts of WA, the southern NT, and southern Tasmania, shifting to low accuracy for central and southwestern parts of WA.

Warmer October to December days likely for the north, west and far south-east, cooler days for central and eastern Australia

  • Maximum temperatures for October to December are likely to be above median for the far north of Australia extending down western WA, southern Victoria, and Tasmania (greater than 60% chance). Below median daytime temperatures are more likely for the far south coast of WA, the south-east NT, northern SA, southern Queensland, and the northern two-thirds of NSW (chance of exceeding the median is 30 to 40%).
  • In October and November, the pattern for maximum temperatures is similar to the three months, although the area of cooler days across the east is broader in October.
  • Minimum temperatures for October to December are likely to be warmer than median for most of Australia (chances are greater than 60%). However, parts of southern and northern WA have roughly equal chances of above or below median overnight temperatures (chance of exceeding the median is close to 50%).
  • Likewise, minimum temperatures for October and November are likely to be above median for most areas, with much of WA and areas near the Queensland-NSW border having roughly equal chances of above or below median overnight temperatures.
  • Past accuracy for October to December maximum temperatures is high to very high for almost all of Australia. For minimum temperatures, accuracy is high across the far north, western and central  WA extending to western SA, south-east Queensland extending down eastern NSW into Victoria and Tasmania, with moderate to low accuracy for northern WA, extending into the central and southern NT and across to the central coast of Queensland, and also parts of eastern SA and western NSW.

Climate influences

  • The negative Indian Ocean Dipole (IOD) has weakened, with IOD values at marginal negative IOD levels. However, the pattern of sea surface temperatures in the Indian Ocean may be providing conditions conducive for rainfall across some parts of Australia.
  • The El Niño–Southern Oscillation (ENSO) is currently neutral, although the tropical Pacific has been cooling over the past two to three months. Climate models indicate further cooling of the tropical Pacific is likely over the coming months, with three of the seven models surveyed by the Bureau cooling enough to meet La Niña criteria, while two additional models briefly touch La Niña thresholds. The Bureau has lifted its ENSO Outlook status to La Niña WATCH, meaning around a 50% chance of La Niña forming. This is approximately double the normal likelihood. The cooling of the tropical Pacific is also likely contributing to the wetter than median outlooks.
  • The Southern Annular Mode (SAM) has mostly been positive for the past three to four weeks. Outlooks indicate positive SAM is likely to continue for the coming three weeks, and also more generally for October to December. The seasonal outlook is a combination of a strengthened polar vortex forecast, and also the La Niña likelihood. A positive SAM during spring months typically brings wetter weather to eastern parts of Australia, but may be drier for western Tasmania.
  • Australia's temperature and rainfall variability are also influenced by global warming caused by human activities. Australia's climate has warmed by around 1.44 °C for the 1910–2019 period, while southern Australia has seen a reduction of 10–20% in cool season (April–October) rainfall in recent decades. Rainfall across northern Australia during its wet season (October–April) has increased since the late 1990s with a greater proportion of high intensity short duration rainfall events.
  • 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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