Spring is the season when southern Australia typically experiences strong contrasts in day-to-day weather, and that will definitely be the case this week.

Heat, rain, storms, lightning, strong winds and even potentially some snow in elevated parts of the southeast are all in this week’s mix, as a series of troughs cross the country with cold fronts brushing the southwest and southeast corners of the country.

Here’s a quick summary of the expected weather conditions in southern Australian each day this week until Sunday.

Tuesday, September 29

After Western Australia was lit up by well over a million lightning strikes in the two days leading up to Monday morning, the WA sky show has eased off for now, although a fresh burst of showers will push into the South West Land Division later on Tuesday associated with an approaching cold front.

The cloudband that delivered heavy rain to large parts of WA’s inland is now tracking towards South Australia. Ahead of it, the mercury is rising rapidly in SA and western Victoria.

Parts of Adelaide had already topped 30°C by 10 am (ACST) this Tuesday, and Adelaide is expecting a maximum of 35°C, which would be its hottest day since February. Adelaide’s hottest September day on record of 35.1°C is potentially at risk of being broken today.

Wednesday, September 30

Showers and some storms move into parts of South Australia as the cloudband entrenches itself over the state. Adelaide enjoys some welcome showers to round out what has been a very dry September after strongly above-average rainfall in May, June, July and August.

The heat spreads all the way east to places like Canberra, which is set for maximums around 25°C on both Wednesday and Thursday. The national capital has ridden the temperature roller coaster this week, with Saturday’s top of 27.2°C followed by Sunday’s chilly 13.5°C as a cold front swept through.

Thursday, October 1

Image: Accumulated rainfall across SE Australia up until 11 pm (AEDT) on Monday, October 5, 2026. Much of the rain shown in Victoria will fall on Thursday and Friday. Source: Weatherzone. 

While AFL Grand Final day looked super soggy to television viewers, only 1.4 mm of rainfall was recorded in the 24 hours between 9 am Saturday and 9 am Sunday at Melbourne’s main city weather gauge, which is virtually across the road from the MCG.

Melbourne will finish up September 2026 with only about a third of its average monthly rainfall of 56.8 mm. But October will start with a soaking, and Thursday could see rainfall totals in the vicinity of 20 mm in the city, while other parts of Victoria are also in line for a healthy drop of rain.

Possible afternoon and evening showers thunderstorms are also in the forecast for Melbourne, while much of Victoria and nearby parts of southern New South Wales will also see showers and possible storms.

Friday, October 2

Image: Mean sea level pressure and precipitable water across Australia predicted for 10 am (AEST) on Friday, October 2, 2026. Source: Weatherzone.

The cloudband crossing Australia has been fed by tropical moisture which has travelled all the way from the Indian Ocean.

On Friday, a new element is added to the equation, as a cold front flicks the southeast, with some models suggesting a cut-off low developing over the SE inland. The day looks likely to be particularly wet over the high country, while cities like Albury-Wodonga and Canberra are in line for their wettest day in a month or longer.

Sydney and parts of the central and southern NSW coastline will also likely see some rainfall later in the day as the rainband crosses the east coast

Much cooler air will also set in over the southeast on Friday, with Melbourne heading for a maximum of just 15°C (October’s average maximum is 19.7°C). Hobart is also expecting a high of 15°C after several days of maximums in the low-to-mid twenties.

The weekend (Saturday, October 3 and Sunday, October 4)

Cool, showery weather will persist across much of the southeast on Saturday, with snow possible at the highest elevations of the Australian Alps. A drying trend begins to establish itself by Sunday.

As an onshore easterly flow establishes over the east coast later in the weekend, showers are likely to become more frequent along the coastal fringe of eastern Vic, NSW, and SE Queensland.

At this stage, it’s still a little early to predict conditions during the NRL Grand Final between the Sydney Roosters and Newcastle Knights, which kicks off at Accor Stadium at 7:30 pm on Sunday evening. But at least some showers are expected across the Sydney basin on Sunday, and it’s worth keeping a close eye on our Sydney Olympic Park forecast.