The national mean temperature came in 0.98 C warmer than the 1961–1990 average to mark the nation's eighth-warmest year on record, according to the Bureau of Meteorology.
Both the mean annual maximum and minimum temperatures were above average for all states and the Northern Territory, the bureau said in its annual climate summary published on Friday.
Despite starting the year under the La Niña climate pattern, unseasonably widespread warmth in the latter months bumped up mean national temperatures.
Frequent low-to-severe intensity heatwave conditions saw parts of northern and central Australia swelter between October to December.
The August to October period was Australia's driest three month period on record since 1900 with surface water storages declining, including those in the Murray–Darling Basin.
It was a much different start to the year with catastrophic flooding wreaking havoc across inland and northern regions.
Above average rainfall lashed much of northern Australia but it was below average for much of the southeast and Tasmania.
Nationally averaged rainfall remained high at 1.7 per cent above the 1961–1990 average.
Forecasters said the major feature of the climate of 2023 was extreme and record-breaking warmth in the global oceans, record-breaking warmth for combined land and ocean temperatures, and a large reduction in annual sea ice around Antarctica.
The average global temperature reached 17.01C for 2023, surpassing the August 2016 record of 16.92C, Reuters reported.
The hottest day ever recorded globally was July 3, according to data from the US National Centres for Environmental Prediction.
The year was also provisionally the United Kingdom's second warmest on record, the Met Office weather service said.
The heat in China was unrelenting with temperature records broken from Beijing to Shanghai as most of the country experienced 2023 on average 0.5 - 1C warmer.
A total of 127 national weather stations across the country broke records for daily high temperatures throughout the year, state media reported on Tuesday.
Beijing smashed a 23-year-old record in July with 27 consecutive days of temperatures above 35C.
The national average temperature of 10.7C, broke the record of 10.5C set in 2021, state broadcaster CCTV said.
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