Climate outlook for June to September

Long-range forecast overview

• For June to August, below median rainfall is likely to very likely (60% to greater than 80% chance) for much of Australia.
• June to August maximum temperatures are likely to very likely (60% to greater than 80% chance) to be warmer than median for virtually all of Australia.
• Above median June to August minimum temperatures are likely to very likely (60% to greater than 80% chance) for most of the country excluding some inland regions.
• This forecast is being influenced by several factors including an ENSO-neutral pattern (neither El Niño nor La Niña) tending towards El Niño in the latter part of the forecast period, and the chance that a positive IOD event may develop in the coming months, as well as longer-term trends.

Drier than average June to August for much of Australia

• For June, below median rainfall is likely (60 to 80% chance) for western parts of WA, Victoria and NSW west of the Great Dividing Range, south-east NT, eastern SA and parts of Queensland.
• For June to August, below median rainfall is likely (60 to 80% chance) for the majority of Australia, with south-western WA, south-eastern SA, majority of Victoria and southern NSW very likely (greater than 80% chance) to be below median. Northern and central parts of WA, northern parts of the Top End of the NT and Queensland, and Western Tasmania mostly have roughly equal chances of above or below median rainfall.
• For June to August, southern and north-western parts of the continent are at least twice as likely to receive unusually low rainfall (amongst the driest 20% of records at this time of the year), including broad areas of the south-west and south-eastern parts of the country.
• Past accuracy of June to July long-range forecasts for chance of above median rainfall has generally been moderate to high for most of Australia increasing to high to very high for southeast Queensland and inland NSW. Accuracy is low for much of the northern tropics.

Warmer than average days for most of Australia during June to August

• For June, above median maximum temperatures are likely to very likely (60% to greater than 80% chance) for most of the country, excluding small areas of the northern tropics.
• During June to August above median maximum temperatures are very likely (greater than 80% chance) for much of Australia, decreasing to likely (60 to 80% chance) for most areas of the top third of Australia.
• The southern two-thirds of Australia is at least twice as likely to experience unusually high maximum temperatures during June to August (amongst the warmest 20% of records at this time of the year), with areas of Tasmania, Victoria, NSW and the WA South West Land Division more than four times as likely to experience unusually high maximum temperatures.
• For June, above median minimum temperatures are likely to very likely (60% to greater than 80% chance) for Tasmania, Victoria, coastal NSW and southern Queensland, the Cape York Peninsula, southern SA, most of WA and northern NT.
• For June to August, minimum temperatures are likely to very likely (60 to greater than 80% chance) to be above median for most of the country, excluding central and eastern inland regions.  
• Past accuracy of May to July long-range forecasts for chance of above median rainfall has generally been high for to very high for most of Australia. Accuracy is low for parts of the Gulf Country in QLD and northern parts of WA and NT.

Climate influences

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

• The Pacific Ocean is currently ENSO- neutral and the ENSO Outlook remains at El Niño WATCH. Oceanic ENSO indicators have continued to warm recently, but there has been little shift towards El Niño in atmospheric ENSO indicators. Long-range forecasts currently suggest El Niño development during winter. Long-range forecasts for La Niña/El Niño increase in accuracy as winter approaches. El Niño increases the chances of below average rainfall for eastern Australia.
• The Indian Ocean Dipole (IOD) is currently neutral. All five models suggest that a positive IOD event may develop by June. A positive IOD typically supresses winter and spring rainfall over much of Australia, and if it occurs with El Niño, it can exacerbate the drying effect. Long-range forecasts of IOD made in autumn have lower accuracy than those made at other times of the year.
• The Southern Annular Mode (SAM) index is currently positive expected to return to neutral towards the towards the end of May. At this time of the year, SAM has little influence on Australian rainfall patterns. As we head into winter, positive SAM typically reduces rainfall across south-western and south-eastern parts of the continent.
• Sea surface temperatures are forecast to be warmer than average surrounding much of Australia, but closer to average to the north and west of Australia and near NSW. A small cool anomaly is likely adjacent to the coast of NSW.
• Longer-term trends: Australia's climate has warmed by around 1.47 °C in the period 1910–2021, leading to an increase in the frequency of extreme heat events. Southern Australia has seen a reduction of 10 to 20% in cool season (April–October) rainfall in recent decades.
• Since the 1990s, in the absence of strong 'wet' drivers, autumn rainfall in southern Australia has generally been below average.