Climate outlook for October to January

Long-range forecast overview

• October to December rainfall is likely to be below median for much of Australia.
• October to December maximum temperatures are at least 3 times as likely to be unusually warm for most of Australia.
• October to December minimum temperatures are very likely to be above median almost nationwide.
• The long-range forecast is influenced by several factors, including El Niño and positive Indian Ocean Dipole events, and record warm oceans globally.

Drier than median October to December likely for much of Australia

• For October, below median rainfall is likely to very likely (60% to greater than 80% chance) for most of Australia, apart from north-western WA and southern Tasmania.
• October to December rainfall is likely (60 to 80% chance) to be below median for much of Australia excluding most of central and northwestern WA and south-west Tasmania.
• Unusually low rainfall for October to December is at least twice as likely for parts of southern, eastern, and northern Australia. Unusually low rainfall equates to the driest 20% of October to December periods from 1981 to 2018.
• Past accuracy of October to December long-range forecasts for the chance of above median rainfall is moderate to very high for most of Australia, decreasing to low to very low for south-western and interior WA, south-western NT and north-western SA.

Warmer than median October to December days and nights for almost all of Australia

• For October to December, above median maximum temperatures are very likely (greater than 80% chance) for almost all of Australia.
• For October to December, most of Australia is at least 3 times likely to experience unusually high maximum temperatures, with chances increasing to more than 4 times likely for most of WA, southern Queensland, and northern NSW. Unusually high maximum temperatures equate to the warmest 20% of October to December periods from 1981 to 2018.
• For October, above median minimum temperatures are likely (60% to 80% chance) for Tasmania, southern and eastern Victoria, eastern and northern NSW, southern Queensland and southern and western WA, increasing to very likely (greater than 80% chance) for the rest of WA. Below median minimum temperatures are likely for some northern tropical regions and eastern SA.
• For October to December, minimum temperatures are likely to very likely (60% to greater than 80% chance) for almost all of Australia apart from south-east SA, and a small area of Queensland's North Tropical Coast.
• For October to December, broad areas of Australia are at least twice likely to experience unusually high minimum temperatures, with chances increasing to more than 4 times likely for parts of central WA, southern Queensland, and northeastern NSW. Unusually high minimum temperatures equate to the warmest 20% of October to December periods from 1981 to 2018.
• Past accuracy of the October to December long-range forecast for chance of above median maximum temperatures has been high to very high across almost all of Australia. For minimum temperatures, accuracy is high to very high for most of Australia, dropping to low to moderate for a small region of north-western Australia.

Climate influences

The long-range forecast reflects known impacts from several significant climate drivers:

• El Niño is underway. Models indicate further warming of the central to eastern Pacific is likely, with sea surface temperatures remaining above El Niño thresholds until at least early 2024. El Niño typically leads to reduced spring rainfall for eastern Australia.
• A positive Indian Ocean Dipole is underway. All models indicate that this positive IOD will persist until at least the end of spring. A positive IOD typically leads to reduced spring rainfall for central and south-east Australia.
• When a positive IOD and El Niño occur together, their drying effect is typically stronger and more widespread across Australia.
• The Southern Annular Mode (SAM) index is currently near positive SAM values but this is expected to be short-lived with forecasts indicating a return to neutral SAM most likely for the coming week.
• Australia's climate has warmed by ~1.48 °C since 1910, leading to an increase in the frequency of extreme heat events. Southern Australia has seen a 10–20% reduction in cool season (April–October) rainfall in recent decades.

The Bureau's climate model simulates the physics of atmospheric, oceanic, ice, and land surface processes and uses millions of observations from satellites as well as in-situ instrumentation on land and at sea. These simulations enable the model to account for the influence of climate change and natural climate drivers like ENSO, IOD, the Madden–Julian Oscillation (MJO) and SAM in its long-range forecasts.