Climate outlook for December to March

Long-range forecast overview

• December to February rainfall is likely (greater than 60% chance) to be above median in eastern parts of the eastern states. Below median rainfall is likely for parts of Western Australia.
• December to February maximum temperatures are likely (greater than 60% chance) to be warmer than median for most of Tasmania, and most of northern and western Australia. Below median temperatures are likely for south-eastern parts of Queensland, central and eastern New South Wales and most of Victoria.
• December to February minimum temperatures are likely to very likely (greater than 60% to greater than 80% chance) to be warmer than median for most of Australia. Below median temperatures are likely for parts of north-east New South Wales.
• This wet outlook over northern and eastern Australia is consistent with several climate drivers, including La Niña, a rapidly decaying negative Indian Ocean Dipole event, a positive phase of the Southern Annular Mode, and record warm waters around Australia.

Above median rainfall for December to February likely for large parts of eastern Australia, below median likely for parts of Western Australia

• During the coming fortnight, the chance of exceeding median rainfall is unlikely to very unlikely (less than 40% to less than 20%) across most of northern Australia. For the Top End and Kimberley this fortnight is forecast to be in the driest 20% of fortnights at this time of year during 1981 to 2018. For most of southern Australia the chance of exceeding median rainfall is around 50%.
• For December, above median rainfall is very likely (greater than 80% chance) for the tip of Cape York and is likely (greater than 60% chance) around the Gove Peninsula Coast of Northern Territory, eastern Queensland, the New South Wales south coast and eastern Tasmania. Below median rainfall is likely for most of north-west and central Australia.
• For December to February as a whole, above median rainfall is likely (greater than 60% chance) around the Queensland ranges and coast, coastal and southern New South Wales, eastern and central Victoria, parts of south-eastern South Australia and all of eastern Tasmania. Below median rainfall is likely for much of Western Australia. 
• Past accuracy of December to February long-range forecasts for chance of above median rainfall is moderate to high for eastern and western parts of Australia, with skill being moderate to low for parts of central and northern Australia, as well as southern Tasmania.

Warmer days for December to February likely for western and northern parts of Australia and Tasmania; cooler for the south-eastern mainland

• During the coming fortnight, above median maximum temperatures are very likely (greater than 80% chance) for all of northern Australia away from the Queensland coast, where the chance of exceeding median maximum temperature varies from 30% in the south to 70% in the north. Below median maximum temperatures are very likely (greater than 80% chance) along southern and eastern coastal zones of Australia.
• For December, above median maximum temperatures are likely (greater than 60% chance) for most of Western Australia, the Northern Territory and into western Queensland and northern South Australia. Below median maximum temperatures are very likely (greater than 80% chance) for south coastal Western Australia, most Victoria, New South Wales, Queensland's south east and Cape York and Arnhem district of the Northern Territory.
• December to February maximum temperatures are likely (greater than 60% chance) to be above median for most of Western Australia, Northern Territory, South Australia and Tasmania. Maximum temperatures are likely to be below median for Victoria, most of New South Wales except for the far west and south-eastern Queensland.
• For December, minimum temperatures are likely (greater than 60% chance) to be above median for north-east Australia and for Tasmania. Chances increase to very likely (greater than 80% chance) for Far North Queensland and Arnhem district of the Northern Territory. Below median minimum temperatures are likely over southern parts of Western Australia and central and eastern parts of New South Wales.
• December to February minimum temperatures are likely to very likely (greater than 60% to greater than 80% chance) to be warmer than median for most of Australia, except over the Southern Interior of Western Australia, western South Australia and around the Northern Tablelands and Central Slopes of New South Wales extending into southern parts of Queensland where temperatures are more likely to be below median.
• For the coming fortnight, for December and for December to February, there is at least a two-and-a-half times the usual chance of unusually warm minimum temperatures for northern parts of the Northern Territory and Queensland. Chances increase to at least four times the usual chance for the Cape York Peninsula and Top End.
• Past accuracy of the December to February chance of above median maximum temperature long-range forecasts is high to very high across most of Australia, with the exception of central parts of Northern Territory, where it is low to moderate. For minimum temperatures, accuracy is moderate to high for most of Australia, with moderate to low skill in pockets of the tropics.

Climate influences

Long-range forecasts reflect several significant climate influences. These include:

• La Niña continues in the tropical Pacific. Outlooks suggest La Niña may start to ease in mid to late summer. During summer, La Niña typically increases the chance of above-average rainfall for northern and eastern Australia.
• The negative Indian Ocean Dipole (IOD) index has been at neutral levels for four consecutive weeks. If the IOD index remains at neutral levels into December the Bureau will consider the 2022 negative IOD event over. The IOD has little influence on Australian climate while the monsoon trough is in the southern hemisphere (typically December–April).
• The Southern Annular Mode (SAM) index is positive and likely to be positive to neutral through December, boosted by La Niña and a strong polar vortex. In summer, positive SAM typically increases the chance of above-average rainfall for parts of eastern Australia and below-average rainfall for western Tasmania.
• Sea surface temperatures have remained warmer than average across Australia's northern tropics and in the Coral Sea. This pattern is likely to be contributing to wetter seasonal outlooks.
• The Madden-Julian Oscillation (MJO) pulse will move into the western hemisphere and slowly weaken. In the coming fortnight rainfall across northern Australia may be below average as the MJO moves further east.
• Longer-term trends: Australia's climate has warmed by ~1.47 °C in the period 1910–2021, leading to an increase in the frequency of extreme heat events. In recent decades, there has also been a trend towards a greater proportion of rainfall from high intensity short duration rainfall events, especially across northern Australia during their wet season.

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 long-range forecasts.