“It’s very likely that NSW will be amongst the warmest three years on record for both mean temperatures and maximum temperatures,” Ms Tobin said.
Despite late rains – often connected to storms and even flash-flooding in places – NSW was also likely to post among its 10 driest years on record, she said.
Sydney just cleared the 1000-millimetres mark for rainfall – by 0.2 millimetres – but that was well shy of its long-run average of 1215.7 millimetres, based on bureau records going back to 1858. It was the driest year since 2014.
Victoria’s 2018 was marked by both days and nights being above average for temperatures. The state was likely to have had a top-10 year for both warmth and dry conditions.
Melbourne itself had a “very dry year”, while maximum temperatures will come in about a degree above the norm, Ms Tobin said.
Indeed, almost all of south-eastern mainland Australia, including the eastern half of South Australia, was on track to record below to very much below average rainfall for the year. The April-September period was the fourth-driest on record for southern Australia.
The national temperature readings will have been given a nudge higher in the final month, which included record-smashing heat in northern Queensland.
For the past week, a blocking high-pressure system in the Tasman Sea has created ideal conditions for heat to intensify over inland Australia.
Records have fallen for daytime and night-time readings in places ranging from Marble Bar in the Pilbara to Alice Springs in the red centre, to Albury in the south-east.
“The pattern doesn’t change for the next week,” said Gabrielle Woodhouse, duty forecaster from the bureau.
The heat will again build up by the end of the week, with parts of north-western Victoria and south-western NSW likely to reach 45 degrees by Saturday, the bureau forecasts.
Australia was hardly alone in recording a hot year.
“For the globe as a whole, 2018 is likely to be the fourth-warmest year on record, continuing the recent pattern of very warm years,” the bureau said.
Temperatures are now about 1.1 degrees above the pre-industrial norm. That’s more than half way to the 2-degree upper limit of warming almost 200 nations agreed to work towards under the Paris climate agreement signed in 2015.
Every year since 1978 has been above the 1961-90 average for mean temperatures, the bureau said.
Peter Hannam is Environment Editor at The Sydney Morning Herald. He covers broad environmental issues ranging from climate change to renewable energy for Fairfax Media.