Soaring temperatures, heat at altitude and hot summer nights combine to create one of south-eastern Australia’s ‘most significant’ heatwaves
by Petra Stock
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Heatwaves and hot days during an Australian summer may seem unremarkable. Days spent at the beach, sunburn and mosquitoes are part of the national psyche, along with outback pubs serving crisp lager as relief from searing afternoon heat.
But when the opal mining town of Andamooka (population 262) in the far north of South Australia reached 50 degrees on Thursday, it was only the eighth time in recorded history anywhere in Australia.
It was also the highest temperature recorded so far in what meteorologists have dubbed a “dome of heat” that began with exceptional temperatures in the west and moved into south-eastern Australia, where it still lingers. With no cold front to clear it out, the heat had “nowhere to go” – trapped by a blocking high in the Tasman and remnants of ex-tropical cyclone Luana in Western Australia.
It’s difficult to compare one heatwave with another – this one came hot on the heels of one earlier in January, which scientists say was made five times more likely by global heating. During that event the fires that ignited across Victoria burnt 435,000 hectares of land (1.1m acres), and killed thousands of flying foxes in the worst mass fauna mortality event since the Black Summer of 2019–20.
But Bureau of Meteorology senior climatologist Dr Simon Grainger says the latest heatwave is worse. For south-east Australia, it is among “the most significant we’ve ever seen”, he says, for its intensity, duration, temperatures and for the length of time the heat has remained above certain thresholds – comparable to January 2009 and January 1939.
Temperature records tumble
About 50 weather stations – mostly scattered across western New South Wales, western Victoria and eastern South Australia – have recorded their highest temperatures, Grainger says.
Victoria set a state all-time record of 48.9C on Tuesday in the Mallee towns of Hopetoun and Walpeup. On the same day, just over the border, the village of Pooncarie hit 49.7C, equalling the second highest temperature recorded in NSW.
Ski fields hotter than 30C
In Australia’s alps, where an average January day might be expected to reach 18C, temperatures climbed above 30C for the first time.
On 28 January, the ski town of Falls Creek recorded 30.5C, and Perisher Valley in NSW reached 30.8C – records for both places. “Those are pretty remarkable temperatures,” Grainger says.
In comparison, on the same day, Melbourne was 23.6C, and Sydney 28.5C, he says. “We were seeing higher temperatures 1,700 metres above sea level than we were [experiencing] down in Melbourne and Sydney at sea level.”
Hot summer nights hard to bear
Not surprisingly, during such events, the spotlight falls on record breaking heat recorded during the day. But overnight temperatures can be even more damaging.
On Monday in Adelaide, people craving relief after the mercury hit 44.7C – the city’s hottest day since 2019 – had to sweat through their hottest night since records began, with temperatures dipping to only 34.1C – about 18C above average – before quickly rising back above 40.
Dozens of inland towns and cities across South Australia, Victoria and NSW have faced five days or more above 40C. In some places, such as Albury in NSW, the heat might last for a week.
Graeme McCrabb, from the western NSW town of Menindee where temperatures reached 49.1C on Tuesday, says the heat left everyone ducking for cover. “They get off the streets, get inside and in front of air con.”
Towns including Maree in South Australia, and Wilcannia and White cliffs in NSW, sweated through three consecutive days of at least 48C, Grainger says. “For New South Wales, that’s never been seen before.”
Such prolonged heat “becomes really hard to bear, because people’s reserves just get worn down,” says A/ Prof Mark Putland, the director of emergency medicine at Royal Melbourne hospital.
“People’s houses just heat up. It gets difficult when it doesn’t cool down at night and people don’t get any relief.”
Hospital admissions soar
Extreme heat is the most common cause of weather-related hospitalisations in Australia, killing more people than all other natural hazards combined. Stifling conditions, and sleep-less nights can be a deadly combination.
“Even while you’re asleep, extreme overnight heat can be dangerous,” warns Dr Caroline McElnay, Victoria’s chief health officer. “When temperatures stay high overnight, your body can struggle to cool down, increasing the risk of heat stress or more dangerous heatstroke.”
It’s still too early to know the full extent of the health affects, but heat-related admissions to emergency departments in Adelaide have tripled compared with January 2025, based on preliminary data.
In Melbourne, authorities issued air quality alerts warning people to stay indoors after smoke from fires burning in the Otways had drifted into the city.
Play continues at the tennis
Amid dire forecasts and heat health warnings, some of the country’s biggest sporting events carried on.
The Australian Open tennis went ahead, despite raised eyebrows, under extreme heat protocols. On the worst days, play on the outer courts was suspended and thousands of fans stayed away, which could cost the tournament an estimated $1m in lower-than-expected ticket, food and beverage revenue. Some are wondering how long it can remain feasible to hold the event outdoors in January as global heating continues to intensify.
Other events have made more substantial changes. The Tour Down Under cycling had been scheduled to traverse its most demanding stage at Willunga Hill, south of Adelaide, as the city was forecast to hit 42C, but the extreme heat and fires prompted organisers to make a last minute change to the route.
Meteorologists expect the heatwave to finally clear the country on Sunday, just as a new month begins. But hotter-than-average days and nights are likely to continue into autumn, according to the latest long-range forecast.
With additional reporting by Melissa Davey and Lisa Cox
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