An extreme heatwave will affect multiple Australian states between Wednesday and Saturday this week. Extreme fire danger ratings are also forecast, with Friday expected to be a particularly dangerous day of fire weather for Victoria.

Heat building in WA

Heat has been building over WA during the last few days with temperatures reaching up to 44.6°C at Onslow on Saturday, 45.5°C at Roebourne on Sunday and 46.4°C at Marble Bar on Monday.

While this intense Pilbara heat may seem distant to those living thousands of kilometres away in Australia’s capital cities, it is an ominous sign of an oppressive heatwave that’s going to spread over other areas of the country later this week.

Heatwave spreading east

Hot air will spread from WA towards southeastern Australia during the remainder of this week, causing temperatures to exceed 40°C over a broad area of the country, covering parts of WA, SA, the NT, Vic, NSW and Qld. Four of these states, WA, SA, Vic and NSW, could even see the mercury exceeding 45°C by Friday.

The heat will be intense and persistent enough to be classified as a severe to extreme heatwave over part of every Australian state and territory this week.

Image: Heatwave severity forecast for the three days starting on Wednesday, January 7, 2026. Source: Weatherzone.

Cities and towns to swelter

Adelaide and Melbourne will be in the thick of this week’s hot air mass over the next few days. Maximum temperatures are predicted to reach 41°C in both cities on Wednesday, with Adelaide also tipped to hit 39°C on Thursday and Melbourne 38°C on Friday.

Further inland, the heat will be relentless. Renmark in SA could see three consecutive days reaching 44 to 46°C from Wednesday to Friday, while Mildura in Vic is forecast to reach 44 to 45°C on each of these three days. Overnight minimum temperatures in the mid-to-high twenties will make this run of heat feel oppressive.

Sydney is also predicted to have four days over 30°C from Wednesday, peaking at around 39°C in the city and 44°C in the western suburbs on Saturday.

This will be the hottest run of days in years for some areas. The last time Mildura had three days in a row above 43°C was in January 2019. Bankstown, which is forecast to reach 38 to 44°C from Thursday to Saturday, hasn't had three consecutive days over 37°C since 1994.

Extreme fire danger ahead

This week’s heat will combine with dry air and blustery winds to cause dangerous fire weather in parts of southern Australia, particularly SA, Vic and southern NSW.

Fire danger ratings are predicted to reach the extreme category – one level below catastrophic – in parts of SA and Vic from Wednesday to Friday, and possibly in southern NSW on Saturday.

Image: Forecast fire danger ratings for Friday, January 9, 2026. Source: Weatherzone.

Friday will be a dangerous day for fires in Vic, as temperatures in the low to mid-forties combine with wind speeds possibly exceeding 40km/h and gusts exceeding 70 km/h. A wind change will further exacerbate the risk of fires becoming difficult to control in Vic on Friday.

Unfortunately, fires are already burning in parts of Vic and smoke could be seen billowing from a large fire to the east of Albury-Wodonga on Monday and Tuesday. This fire was not under control as of midday on Tuesday and will likely become more difficult to manage over the coming days, with Albury-Wodonga forecast to reach 41 to 43°C between Wednesday and Friday.