Heat dome to push southeastern Australia toward record temperatures, raising bushfire risk

By late next week, the forecast high for the northwestern Victorian town of Ouyen reads like a sequence pulled from a different climate: 44, 46, 47—possibly 48 degrees Celsius.

That stretch of temperatures, expected from the weekend through at least Tuesday, is part of a severe heatwave bearing down on South Australia, Victoria and New South Wales. Forecasters say a broad “heat dome” could push some inland centres close to their all-time temperature records and elevate bushfire danger to extreme or even catastrophic levels.

Australia’s Bureau of Meteorology warned on Thursday of “severe to extreme heatwave conditions” across large parts of southern and southeastern Australia from around Saturday, Jan. 24, through much of the following week. A large, slow-moving high-pressure system is expected to park over the region, trapping and compressing hot air and sending maximums widely above 40C.

“We’re looking at possible record-breaking heat bringing severe to extreme heatwave conditions and also extreme to possibly catastrophic fire danger to parts of southeastern Australia over the next week,” bureau meteorologist Christie Johnson said in a media briefing.

Forecasts near record territory

The focus of the late-January heat is expected to be inland South Australia and Victoria, and parts of inland New South Wales—particularly along and north of the Murray River and across the western plains.

In Victoria’s Mallee district, Ouyen is forecast to climb to about 48C early next week, while Mildura, on the Murray River, is expected to reach around 47C. Forecasters say if those numbers are reached, they would challenge January records and, in some cases, come close to all-time highs for those locations.

“Many centres are probably going to approach their all-time maximum records,” bureau forecaster Kevin Parkin told reporters, adding that a “dome of heat is expected to sit over Victoria, not just this weekend but persisting well into next week.”

In South Australia, Adelaide is tipped to reach about 42C to 43C on key days, with inland areas hotter again. Port Augusta, at the top of Spencer Gulf, is forecast to climb to around 46C, and pastoral districts to the north and west are expected to see several days in the mid-40s.

In New South Wales, the worst of the heat is expected to build from Sunday. North-west inland centres such as Moree are facing at least a week of 40-plus days, with forecasts of about 43C on Australia Day, Jan. 26, and 45C mid-week. In the far west, around White Cliffs, local forecasts point to maximums near 47C for three days in a row.

The same high-pressure system has already scorched parts of Western Australia. Earlier in the week, the Shark Bay area reached 49.2C and Carnarvon climbed to 47.9C, close to historic peaks for those stations.

Across much of the affected region, temperatures are expected to run 8 to 16 degrees above the late-January average, according to the bureau.

What is a heat dome?

Meteorologists use “heat dome” to describe a broad, persistent high-pressure system that effectively caps the atmosphere, trapping hot air near the surface. Under high pressure, air sinks and warms, skies clear, and there is little convection to generate storms or bring in cooler air.

In this case, the subtropical ridge of high pressure that baked Western Australia earlier in the week has shifted east across the continent. A blocking pattern in the broader atmosphere—helped by an active monsoon trough over northern Australia—has slowed weather systems and allowed the heat to build rather than move on quickly.

That setup is particularly dangerous in late January, when soils and vegetation in southern Australia are already dry after spring and early summer. For many areas of South Australia and Victoria, the late-month heat will arrive on top of earlier January heatwaves and a lack of significant rain.

Fire risk in already burned country

Fire agencies in three states are warning that the coming days could bring the most dangerous fire conditions since the 2019–20 Black Summer bushfires.

Parts of South Australia and southern New South Wales are already under extreme fire danger ratings, with authorities warning those could be upgraded as temperatures climb and winds freshen. South Australia’s Country Fire Service has flagged extreme fire danger for districts including the Yorke Peninsula and parts of the pastoral interior. The New South Wales Rural Fire Service has issued total fire bans in several southern and central districts ahead of the weekend.

In Victoria, the Country Fire Authority and Forest Fire Management Victoria are watching closely as the heat returns to areas that burned earlier this month. Out-of-control bushfires around Longwood and Walwa and blazes in eastern alpine and coastal regions prompted a state of disaster declaration in early January, with at least 130 homes and other buildings destroyed.

Premier Jacinta Allan described one of those earlier days as “the most dangerous day we have had in years,” saying firefighters were working in “the toughest conditions imaginable.” CFA chief officer Jason Heffernan called the conditions “dire” and urged people not to travel unless absolutely necessary on days of catastrophic fire danger.

While those fires have since been contained or brought under control, the underlying fuels remain extremely dry. With little rain expected during the late-January heatwave, authorities fear new ignitions could spread quickly in forest, grassland and cropping country.

Health systems and cities under strain

Beyond fire, health authorities are warning that prolonged heat poses a serious risk to people—particularly older adults, infants, pregnant women, people with pre-existing medical conditions and those without access to air conditioning.

Unlike some previous heat events, overnight temperatures are expected to stay high in many inland and coastal areas, with minimums in the mid-20s and, in some cases, edging into the low 30s. Without cooler nights, bodies have less chance to recover, increasing the risk of heat exhaustion and heatstroke.

Ambulance services are urging people to stay hydrated, avoid strenuous outdoor activity in the hottest parts of the day, and check regularly on family, neighbours and friends who may be vulnerable. Pet owners are being reminded not to leave animals in cars or full sun and to ensure adequate shade and water.

Major cities are also bracing. Melbourne recorded its hottest day in six years earlier in January when the temperature hit 41C, while Adelaide reached 43C. With temperatures again forecast to climb into the low 40s around the weekend, councils in urban and outer-suburban areas are expected to extend opening hours at public libraries, pools and community centres to provide access to air-conditioned spaces.

Heat is also likely to disrupt the Australian Open tennis tournament in Melbourne, which runs through late January. Under Tennis Australia’s extreme heat policy, matches can be suspended and roofs closed on main courts when on-court conditions reach specified thresholds for temperature, humidity and radiant heat.

Rural livelihoods and the power grid

Inland communities that depend on outdoor work are preparing to adjust schedules or halt activity during the peak of the heatwave.

Farmers across the Mallee, Riverina and western New South Wales are planning earlier starts, extra shade and water for livestock, and contingency plans if power or pumps fail. Construction crews and other outdoor workers are expected to face restricted hours or mandated breaks under workplace safety guidelines when temperatures and humidity reach dangerous levels.

Multi-day heatwaves typically drive sharp increases in electricity demand as households and businesses run air conditioners for longer. Energy operators have warned in past summers that extreme heat—especially when combined with bushfires affecting transmission lines—can increase the risk of supply interruptions and localised blackouts. Network operators in South Australia and Victoria have not issued specific warnings for the coming week but are monitoring conditions closely.

The insurance industry is also watching the developing pattern. After several years of costly bushfires, storms and floods, insurers have raised concerns about rising catastrophe losses and the affordability of cover in high-risk regions, particularly parts of regional Victoria and New South Wales.

A hotter baseline

The Bureau of Meteorology has reported that Australia’s national average temperature is now about 1.5 degrees higher than it was in 1910, when reliable records began. The agency and climate scientists say that warming is contributing to more frequent, intense and longer-lasting heatwaves and to more dangerous bushfire seasons.

Meteorologists have described January’s sequence of heatwaves as the most significant for southeastern Australia since the Black Summer fires, which burned more than 24 million hectares, destroyed thousands of homes and claimed dozens of lives.

As the heat dome settles in over the coming days, authorities are emphasising preparedness rather than alarm. Residents are being urged to follow bureau forecasts and state emergency warnings, to have bushfire survival plans in place where relevant, and to identify cool refuges if their homes are not adequately insulated or air-conditioned.

The heatwave will eventually break as the high-pressure system weakens and cooler air moves in. For many communities facing another run of days over 40 degrees, the question is how often such events will return—and how quickly homes, health systems, energy networks and fire services can adapt to summers in which “under the dome” becomes less an anomaly than a recurring feature.