This summer is on track to be the warmest on record for many parts of NSW and southern Queensland.
And things aren't expected to cool down soon, with March tipped to be hotter and drier than average across most of Australia.
"Further heatwaves are possible," senior climatologist Robyn Duell said in the Bureau of Meteorology's latest climate outlook.
The country's southeast endured a high number of hot days across January and February, which to date rank among the hottest months ever for the region.
January was the warmest month on record for Sydney and Brisbane, while eastern Australia experienced its most severe heatwave since 2009 in the second week of February.
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The bureau said the consistency of high temperatures - more than the extreme temperatures themselves - has made early 2017 an "exceptional event".
Three heatwaves saw unusually high daily maximum and minimum temperatures for at least three consecutive days over large parts of the country.
Moree, in NSW's north, and border town Mungindi suffered through more than 54 days in a row of 35 degrees or above.
The highest temperature recorded during the heatwaves was 48.2 on February 9 in Tarcoola, South Australia, followed by 47.9 on February 12 in Walgett, NSW.
The bureau said this year's warm start is the latest in a string of prolonged or intense spells that have affected Australia roughly every six weeks since 2012.
"Overall, the time between heat events is shortening," it said.
More warmer-than-average days and nights are forecast across most of the country - except the far north - in autumn, with rainfall also likely to be below average for large parts.
