A Brief Burst of Summer Sweeps Across the Southeast

Summer is making an early appearance across parts of South Australia, New South Wales and Victoria this Sunday, with temperatures set to soar into the mid-30s. 

September has already been unusually warm across Australia's southern states, with the persistent warmth contributing to an early end to the ski season at all resorts apart from Perisher Valley. 

Another burst of heat is on the way

A very warm to hot airmass is pushing eastwards across the southern states this weekend, ahead of a cold front currently moving through southern Western Australia. 

Hot summer sun
Image: A very warm to hot airmass with temperatures in the low to mid-30's (figures shown in pink boxes) precede a cold front passing over southern Western Australia as seen in the satellite imagery at 2:55pm AEST Sat 19 Sept 2026. Source: Weatherzone. 

Temperatures have already surged into the 30s across southeast Western Australia and South Australia this afternoon, sitting around 9–10°C above the September average. The warmth extends into Victoria too, with temperatures running well above normal for this time of year. 

At 2:30pm ACST, Ceduna had reached 32.2°C, a remarkable 10.6°C above average for September. Nullarbor was even warmer at 32.9°C, sitting 10.2°C above the September average. 

Heat spreads into eastern Australia 

As the cold front moves into South Australia, the hot airmass will push into inland eastern South Australia, western New South Wales and northwest Victoria, delivering a brief taste of summer on Sunday. 

Daytime temperatures are forecast to reach 8-12°C above the September average, with widespread low to mid-30s expected across the region. 

Image: Forecast maximum temperatures (coloured shading) and mean sea level pressure (white lines) for 4pm AEST 20 September 2026. Maxima in the mid 30's are forecast over inland eastern SA, western NSW and northwest Victoria. Source: Weatherzone. 

Some locations are set to feel more like midsummer than early spring. 

In South Australia, Port Augusta is forecast to reach 34°C, Coober Pedy 36°C and Oodnadatta 37°C. 

Across New South Wales, Tibooburra is forecast to reach 34°C and Broken Hill 32°C. 

In Victoria, Mildura is expected to climb to 34°C, while Swan Hill reaches 31°C. 

But the summer-like warmth won't last. Cooler conditions will sweep back across southeast Australia on Monday as the cold front pushes through, bringing a sharp end to the brief burst of heat. 

For parts of the southeast, it will be a taste of summer — but only for a day.