Australia in Autumn 2023

In brief

• Autumn rainfall was 10.1% below average for Australia as a whole.
• Rainfall for autumn was above average for central Western Australia, the central Northern Territory and north-western Queensland, much of central South Australia and some smaller pockets scattered across the country.
• Significant flooding affected large parts of the eastern Northern Territory and north-western Queensland during autumn due to heavy rainfall at the beginning of March associated with a monsoon trough and a tropical low. Tropical Cyclone Ilsa brought flooding to parts of north-western Western Australia in April.
• Rainfall was below average for much of inland northern New South Wales, adjacent areas of southern Queensland and eastern Soutn Australia, along much of Western Australia's coast extending into inland areas, areas along the east coast of the mainland, parts of  Tasmania and areas scattered across the Northern Territory's Top End and Western Australia's Kimberley.
• The national mean temperature was equal to the 1961–1990 average for autumn, the coolest since 2012.
• The national mean maximum temperature was 0.39 °C above average, while the national mean minimum temperature was 0.40 °C below average, the coolest since 2015 and 2012 resprctively.
• Mean maximum temperatures for autumn were warmer than average for most of the northern half of New South Wales, eastern and southern Queensland, north-eastern South Australia and areas of western and south-eastern Western Australia. Mean maximum temperatures were cooler than average for large parts of the central Northern Territory, western Queensland, Victoria and parts of the  Kimberley in Western Australia.
• Mean minimum temperatures for autumn were warmer than average for parts of far northern Queensland, Western Australia's Pilbara coast, south-east Western Australia and much of western South Australia and the southern half of Victoria. Mean minimum temperatures were cooler than average for much of the Northern Territory, from inland western Queensland through inland parts of the state to parts of the central coast and south-east, much of New South Wales inland of the ranges, eastern South Australia and large parts of north-eastern, western and southern Western Australia.

Further information and tables of records for each state and the Northern Territory can be found in the individual regional climate summaries, to be released on 5 June. For discussion of events during autumn, see the individual monthly climate summaries for Australia for March, April, and May.

Temperatures

The national mean temperature was equal the 1961–1990 average for autrumn, the coolest since 2012.

The national mean maximum temperature was 0.39 °C above average, while the national mean minimum temperature was 0.40 °C below average, the coolest since 2015 and 2012 respectively.

Mean maximum temperatures were warmer or very much warmer than average for most of the northern half of New South Wales,  southern and eastern Queensland and north-easdtern South Australia. Mean maxima were also above average for parts of Western Australia's Gascoyne, Pilbara and Eucla districts.

A heatwave affected much of Australia during a week-long period around the middle of March. Between 17 and 21 March, many sites in New South Wales, and some in South Australia, Victoria and Queensland had their highest temperature on record for autumn.

Mean maximum temperatures were cooler than average for parts of the central Northern Territory and western Queensland, south-western and north-eastern Victoria extending into adjacent areas of south-eastern South Australia and south-eastern New South Wales, and for parts of the Kimberley in Western Australia.

Mean minimum temperatures for autumn were warmer or very much warmer than average for parts of Western Australia's Pilbara coast  and south-east, western South Australia, the southern half of Victoria and the Cape York Peninsula in Queensland.

Mean minimum temperatures were cooler or much cooler than average for much of the Northern Territory, from inland western Queensland through inland parts of the state to parts of central coast and south-east, much of New South Wales inland of the ranges extending into adjacent parts of eastern South Australia, and for most of the Kimberley, Northern Interior, South West Land Division and Eucla in Western Australia. Some stations in Western Australia and South Australia had their lowest autumn mean daily minimum temperatures on record or the lowest for at least 20 years.

Between 5 and 7 May and between 25 and 27 May, cold polar air was directed towards northern parts of the country by south-easterly airflow in the wake of strong cold fronts that crossed south-eastern Australia. Cold air combined with clear skies and light winds under high-pressure systems that followed, resulting in low daily minimum temperatures in large parts of Australia. Many stations across all states (except Victoria) and the Northern Territory had their lowest temperature on record for autumn on 8 and 9 May, and between 27 or 30 May. Oakey Aero (Queensland) recorded -5.7 °C on 9 May; this was the nineth-lowest autumn daily minimum temperature on record in Queensland.

Rank ranges from 1 (lowest) to 114 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Anomaly is the departure from the long-term (1961–1990) average.

Rainfall

Autumn rainfall was 10.1% below the 1961–1990 average for Australia as a whole.

The season begun with a drier than average March, followed by a wetter than average April, while May was Australia's second-driest May on record.

Rainfall was below or very much below average for north-western quarter of New South Wales, adjacent parts of inland southern Queensland and eastern South Australia, along much of Western Australia's coast extending into some inland areas, parts of eastern Queensland, coastal New South Wales and Tasmania, and for pockets of the Northern Territory's Top End and Western Australia's Kimberley.

Rainfall for autumn was above to very much above average for much of central Western Australia and across the central Northern Territory and north-western Queensland. Rainfall was above average for large parts of South Australia's Pastoral districts, some areas of eastern New South Wales on the inland side of the ranges, with pockets of above average rainfall continuing along the ranges in Victoria, and parts of south-west Victoria.

Total rainfall for autumn was the highest on record for some stations in Queensland, Western Australia, South Australia and New South Wales, while a number of other stations had their highest total rainfall in at least 20 years.  

Significant flooding affected large parts of the eastern Northern Territory and north-western Queensland during autumn due to heavy rainfall in the first part of March associated with a monsoon trough and a slow-moving tropical low. Ten-day rainfall totals between 400 and 800 mm were observed in some areas. A few stations with more than 100 years of observations, including Undilla (Queensland) and Alexandria (Northern Territory),  had their highest daily rainfall total on record for autumn between 1 and 10 March.

During mid-April, Tropical Cyclone Ilsa brought high daily rainfall totals and flooding to parts of north-western Western Australia. A cold front then advected moisture from ex-Tropical Cyclone Ilsa bringing widespread heavy rain to inland Western Australia, South Australia and parts of the south-east.

Significant weather and records

For discussion of events during autumn, see the individual monthly climate summaries for Australia for March, April and May.

Further information and tables of records for each state and the Northern Territory can be found in the individual regional climate summaries, to be released on 5 June.

Rank ranges from 1 (lowest) to 124 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Departure from mean is relative to the long-term (1961–1990) average.