Last summer was Australia’s second-hottest on a record going back to 1910, at 1.89C above the long-term average, according to data from the Bureau of Meteorology.
The second-hottest summer – coming after the second-hottest winter and the hottest spring on record – included the second-hottest January and the third-hottest December.
Only the summer of 2018/19, at 2.11C above average, was hotter.
Over the past 15 years, the data shows that only the summers of 2011 and 2001 have been cooler than the long-term average, taken from 1961 to 1990.
“Climate change is the primary ingredient for this summer’s heat,” said Dr Linden Ashcroft, a climate scientist at the University of Melbourne.
“You could not have made this hot summer cake without climate change. It will only get worse if we don’t stop burning fossil fuels.
“There is no way this could have occurred without a heating planet. Yes, this is the second hottest summer on record, but it will be one of the coolest in the 21st century.”
She said the heat had come despite La Niña-like conditions in the tropical Pacific which have in the past been associated with cooler conditions.
Data released by the BoM shows the heat was well-spread around the country, with all regions seeing average daily temperatures in the top six on record.
Last summer ranked second for the hottest daytime temperatures, and fourth-warmest for night-time heat.
On a state-by-state basis, all mainland states had average temperatures in their 10 highest on record for summer. Western Australia had its hottest summer on record, and also its hottest summer for night-time temperatures.
Summer rainfall across the country was only slightly below average, with South Australia and the NT particularly dry.
“I don’t think we should need convincing about climate change any more in Australia because we can feel it,” said Ashcroft.
“We see it in our plants, our weather observations, in our moods and in the decisions that we make. This heat affects people, but we do have the ingredients to stop it.”
The bureau’s long-range forecast covering autumn and released this week, showed that most of Australia should expect typical rainfall levels, but north, east and central Queensland could be drier and it could be wetter in the north-west of the country.
For temperatures, there was an increased chance of unusually high daytime and night-time temperatures across the whole of the country.
