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 parts of northern WA and western Tasmania.
  • Maximum temperatures for October to December are likely to be above median for the northern tropics extending down into central WA, and far south-east Australia. Below median daytime temperatures are more likely for the southern WA coastline and parts of eastern Australia.
  • Above median minimum temperatures for October to December are likely for almost all of Australia, except southern 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.

Above median October to December rainfall likely for eastern two-thirds of Australia

  • Rainfall for October to December is likely to be above median for much of the NT, SA, Queensland, NSW, Victoria and eastern Tasmania (chance of exceeding median is greater than 60%). Much of south-east mainland Australia shows a greater than 80% chance. Conversely, parts of northern WA and western Tasmania are 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 southern SA, with moderate accuracy for western and southern parts of WA, northern Victoria and southwest NSW, extending into northern SA, shifting to low accuracy for central areas of Australia and parts of south-western Australia.

Warmer days for the northern tropics and far south-eastern Australia, but cooler for parts of southern WA and eastern Australia

  • Maximum temperatures for October to December are likely to be above median for tropical northern Australia extending down to central WA, southern Victoria, and Tasmania (greater than 60% chance). Below median daytime temperatures are more likely for southern WA, south-east Queensland, and much of the eastern half 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 November.
  • Minimum temperatures for October to December are likely to be warmer than median for most of Australia (chances are greater than 60%). However, southern WA has 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 southern and western WA 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 southern WA, south-east Queensland extending down eastern NSW into southern and eastern Victoria, and Tasmania, with moderate to low accuracy for northern WA, extending into the central and southern NT, most of SA, and central coast of Queensland.

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. Models suggest this weak negative IOD pattern could persist through October before easing further.
  • The El Niño–Southern Oscillation (ENSO) is currently neutral, although the tropical Pacific has been cooling over the past two 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 there is 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 been positive for the past three weeks. Outlooks indicate positive SAM is likely to continue for the coming three weeks, and also more generally for October to December. The seasonal SAM 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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