Our memory of temperature is a tricky thing. How do you think Australia's 2022-23 summer stacked up against our average summer temperature?
Across the country, this summer was cooler on average than what we’ve experienced this decade. Many of us weren't cranking up the aircon and hiding indoors as often. But if we look at Australia’s average summer temperatures from 1960, this summer was still just above average.
Australia's summer wasn’t cold, we just got used to the heat
Australia's 2022-23 summer had varying temperatures across different regions. Yet as a whole, it was slightly above the long-term average summer temperature. According to the Bureau of Meteorology[Link will open in a new window] (the Bureau), the average temperature of summer was 27.57 degrees Celsius (°C). That's 0.07°C above average.
Summer wasn't the only season heating up. Australia's national mean temperature in the past 12 months was 0.5°C warmer than the 1961–1990 average. That makes 2022 the 22nd-warmest year on record since national temperature records began in 1910.
Our Climate Intelligence Research director Dr Jaci Brown[Link will open in a new window] said it's understandable to think last summer was cooler than usual.
“It’s sometimes hard to remember what the weather felt like a few decades ago. But the data shows us this year wasn’t cold compared to the 70s and 80s," Jaci said.
"The overnight temperatures are making the biggest difference. We see a trend of them increasing, even when the maximum temperatures show less change."
Research team leader of regional projections John Clarke[Link will open in a new window] said prior to the 1970s, we would have regarded this summer as a reasonably hot one.
"Australia hasn’t experienced a below average summer for over a decade. In the past 20 years, there have been 19 hotter than average summers. Only one summer was below average, which was the summer of 2011-12," John said.
“So, although it felt like a cool and wet summer, it was actually just warmer than our long-term average summer. But, given the size of Australia, the story wasn’t the same everywhere,” he said.
Different states record varying temperatures
The Bureau’s data showed northern and much of eastern Australia was slightly cooler and wetter than average. Meanwhile much of southern Australia was warmer and drier than average, especially in the west.
Annual maximum temperatures were above average for most of northern Australia, Tasmania and parts of the west coast. Meanwhile they were below average for New South Wales, southern Queensland and parts of South Australia.
Parts of eastern and central Australia recorded their coolest summer in more than a decade. This included Sydney city, which recorded an average maximum temperature of 26.4°C. But that's still above the long-term average of 25.7°C.
John said the data is not surprising.
"Climate is inherently variable and this variability results in cool years and hot years that occur against a background of the average or long-term climate," John said.
"As our climate is changing and getting hotter over time, the natural variability still occurs. But it’s superimposed over that climate change trend.
"This means there will continue to be cooler and hotter years. But, compared to the past, the cooler years are becoming less common," he said.
La Niña[Link will open in a new window] also brought cooler and wetter conditions to the eastern parts of Australia.
With the rare occurrence of three La Niñas in a row, some areas experienced above average rainfall over summer. Wet soil from earlier wet years contributed to the floods experienced across the country.
What could summer look like in the future?
The State of the Climate 2022 report[Link will open in a new window], co-developed between us and the Bureau, showed Australia warmed on average by 1.47°C (give or take 0.24°C) since national records began. The report projects Australia will experience continued warming in coming decades. With that warming we will see more extremely hot days and fewer extremely cool days.
"Natural variability means we will continue to experience cooler and hotter years. But the odds of having a year below the historic average will continue to decrease over time," John said.
"These changing trends will continue until the world reaches net zero carbon emissions, after which the climate can begin to stabilise."
Jaci said now is not the time to become complacent.
"The temperatures are increasing and we need to be prepared for hot, dry conditions," she said.