Climate outlook for December to March

Long-range forecast overview

• December to February rainfall is likely to be below average across most of north-east Australia, and the northern coastline.
• December to February maximum and minimum temperatures are very likely to be above average for almost all of Australia.
• December to February maximum and minimum temperatures are at least 2.5 times more likely than normal to be unusually high for much of Australia. Unusually high temperatures equate to the warmest 20% of November to January periods from 1981 to 2018.
• The long-range forecast is influenced by several factors, including the active El Niño and positive Indian Ocean Dipole events and record warm oceans globally.

Drier than median December to February outlook for most of the north-east and northern coastline of Australia

• For December and December to February, below median rainfall is likely (60 to 80% chance) for north-east Australia, most of the northern coastline, and small parts of the south-east Australia.
• For December and December to February, large parts of inland Australia have a near equal chance of above or below average rainfall. However, if above average rainfall occurs, it is unlikely to be widespread.
• Past accuracy of December to February long-range forecasts for the chance of above median rainfall is moderate to high for most of Australia, decreasing to low to very low for parts of southern and central Australia, and areas around the Gulf of Carpentaria.

Warmer December to February days and nights for almost all of Australia

• For December and December to February, above median maximum temperatures are likely to very likely (60% to greater than 80% chance) for almost all of Australia.
• For December, above median minimum temperatures are likely to very likely (60% to greater than 80% chance) for most of Australia except western parts of the Pilbara and Gascoyne in WA, and central coastal regions of Queensland. For the former, chances of above or below median temperatures are near equal while for the latter, below median temperatures are likely (60 to 80% chance).
• December to February minimum temperatures are likely to very likely (60% to greater than 80% chance) to be above median for Australia.
• For December to February, most of Australia is at least 2.5 more likely than normal to experience unusually high maximum and minimum temperatures. The chance of unusually high maximum temperatures increases to greater than 4 times more likely than normal for parts of western WA, and the far north of the NT and Queensland. The chance of unusually high minimum temperatures increases to greater than 4 times more likely than normal for most of northern Australia (excluding north-west WA and central coastal Queensland) extending into the southern interior of WA, and the north-eastern half of NSW. Unusually high temperatures equate to the warmest 20% of December to February periods from 1981 to 2018.
• Past accuracy of the December to February long-range forecast for chance of above median maximum temperatures and above median minimum temperatures has been high to very high across almost all of Australia, excluding the interior of NT.

Climate influences

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

• El Niño continues in the tropical Pacific. Models indicate some further warming of the central to eastern Pacific is possible, with SSTs remaining above El Niño thresholds into the early southern hemisphere autumn 2024. In summer, El Niño increases the likelihood of drier than average conditions for the north-east of Australia and warmer than average days across much of the eastern half of the country.
• The positive Indian Ocean Dipole (IOD) event continues and is currently tracking at strong levels. The IOD tends to break down as the monsoon trough moves south into the southern hemisphere, usually around the end of the southern hemisphere spring. Given the current strength of the positive IOD event, the break down this year is likely to be slightly later than usual. All international climate models surveyed by the Bureau suggest the positive IOD is likely to ease in December. A positive IOD typically increases the chance of below average rainfall for central and southern Australia during spring, and to a lesser extent, in early summer.
• The Southern Annular Mode (SAM) index is neutral. Forecasts indicate it will remain neutral for the next fortnight. During spring and summer, a neutral SAM is associated with typical climate conditions for Australia.
• Australia's climate has warmed by ~1.48 °C since 1910, leading to an increase in the frequency of extreme heat events.

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.