Seasonal Climate Outlooks (June to August 2023)

Australia

The long-range Australian forecast issued by BoM on 1 June 2023 states:

• Below median rainfall is likely to very likely (60% to greater than 80% chance) for almost all of Australia.

• Maximum temperatures are likely to very likely warmer than median (60% to greater than 80% chance) for almost all of Australia.

• Above median June to August minimum temperatures likely to very likely (60% to greater than 80% chance) for much of Australia, with below median minimum temperatures likely (60 to 80% chance) for southern parts of the NT and Queensland as well as western NSW and eastern SA.

• This forecast is being influenced by several factors, including likely warming in the tropical Pacific Ocean towards El Niño thresholds, potential development of a positive Indian Ocean Dipole, and record warm oceans globally.

Long-range forecasts reflect several significant climate influences including:

• The Pacific Ocean is currently ENSO-neutral, and the ENSO Outlook remains at El Niño WATCH. Long-range forecasts currently suggest El Niño development during winter. El Niño increases the chances of below average rainfall for eastern Australia and above average daytime temperatures for the southern two-thirds of Australia. http://www.bom.gov.au/climate/outlooks/#/overview/influences

• The Indian Ocean Dipole (IOD) is currently neutral. Long range forecasts suggest that a positive IOD event could develop in winter. A positive IOD typically supresses winter and spring rainfall over much of Australia.

• The Southern Annular Mode (SAM) index is currently positive and is expected to return to neutral during June. During winter, a positive SAM often has a drying influence for parts of south-west and south-east Australia.

• Sea surface temperatures are forecast to be warmer than average surrounding much of Australia including warm anomalies greater than 0.8°C in the Coral Sea and Tasman Sea, but cool anomalies are forecast for parts of the northern coast of Australia, and off the NSW coast during June 2023.

• 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.