Australia recorded its hottest month ever in January, with mean temperatures exceeding 30C (86F) for the first time.
The extreme heat, during the country's summer period, was "unprecedented",
At least five January days were among the 10 warmest on record, with daily national temperature highs of 40C.
The blistering conditions caused wildfire deaths, bushfires and a rise in hospital admissions.
The mean is the average between the average coldest temperature and average hottest temperature.
The new record surpasses conditions recorded in 2013, previously considered the nation's worst heat wave.
"We saw heatwave conditions affect large parts of the country through most of the month," climatologist Dr Andrew Watkins said.
Records were broken for both duration and also individual daily extremes, he said. Rainfall was also below average for most areas.
The fortnight of extreme heat also resulted in the death of up to a million fish in the drought-affected state of New South Wales.
Australia has increasingly endured hotter summer temperatures. Last year,
- its hottest day since 1939.
"The warming trend which has seen Australian temperatures increase by more than one degree in the last 100 years also contributed to the unusually warm conditions," Dr Watkins said.
How is climate change affecting Australia?
Officials have confirmed that 2018 and 2017 were Australia's third and fourth hottest years on record respectively.
Even if global temperatures are contained to the Paris accord limit of a 2C rise above pre-industrial levels,
last year, while
when bushfires swept through Queensland in November.