A cold front will bring unseasonably cold temperatures and heavy rainfall to several major cities.
The front will freeze most of southeastern Australia, while the north will swelter with temperatures above 40 degrees Celsius.
South Australia was the first to feel the cool change on Tuesday morning, with an expected minimum temperature of just 9 degrees Celsius.
Western winds reaching 35 to 45 km/h, turning southwesterly 25 to 40 km/h in the afternoon, will keep the city cold, with temperatures expected to peak at 18 degrees Celsius around noon.
The front will continue to move eastward across Victoria throughout the day.
A cold front will bring wintry temperatures to Hobart, Adelaide, Sydney and Melbourne this week
The cold front will move east from South Australia on Tuesday (photo, a map of temperatures on Thursday)
“We expect cooler winds to reach Melbourne around mid-afternoon, with winds shifting to a more south-westerly direction on Wednesday,” Weatherzone meteorologist Felix Levesque said.
Melbourne will enjoy a high of 26 degrees on Tuesday before the cold front moves across the city.
On Wednesday, the maximum temperature will drop to just 15 degrees Celsius, next to a minimum of 9 degrees.
Aerial meteorologist Alison Osborne warned: ‘It will feel like winter again.’
The cold snap then creeps north into New South Wales, reaching the Sydney region on Wednesday morning.
Sydneysiders will enjoy a warm, sunny day on Tuesday with a high of 28 degrees Celsius.
However, the minimum temperature in the city will drop to 13 degrees Celsius on Friday.
Canberra will also feel the chill with a low of 2 degrees Celsius on Thursday and Friday.
The system will reach Brisbane on Thursday, but the Queensland capital will not experience frigid temperatures like southern capitals with a forecast of up to 31 degrees Celsius.
The cold front will also bring rain to several regions of south-eastern Australia, including the NSW north coast, where firefighters are battling several bushfires.
The cold front, combined with an inland trough, will bring much-needed rain to bushfire-affected areas in New South Wales (photo, North Coast bushfires)
Tuesday will be a relatively dry day, with Hobart receiving most of the rain in the southeast.
Showers are expected to hit the city from Tuesday, with damaging winds possible in the evening.
The wet weather is expected to continue until Friday.
South-west Victoria will see some rainfall totaling around 10mm from Tuesday to Thursday.
Melbourne could see possible showers on Wednesday and Thursday with two-day rainfall totals between 2 and 5mm.
As the front moves across NSW, an inland trough is expected to draw moisture and bring rain.
“Thursday and Friday we could see heavier falls from the mid-north coast to the northern plateaus,” Levesque said.
‘Two-day totals could reach 50 to 80mm in some areas.
‘However, more widespread totals will be between 20 and 40mm.’
Sydney is expected to see some of that rain, with showers forecast on Wednesday, Thursday and Friday.
The rain will come as a relief to firefighters battling wildfires across the state.
On Wednesday, the maximum temperature in Melbourne will drop to just 15 degrees Celsius, alongside a low of 9 degrees
The NSW north coast has been hit hard by fires, with several scared locals sharing photos of flames just meters from their homes.
The national fire brigade shared an update on Monday evening encouraging residents to review their fire plans.
“As of 6 p.m., there are 62 fires burning across the state, 24 of which are not yet contained,” the report said.
‘One fire is listed at Watch and Act level. More than 900 firefighters and incident management specialists are currently working to bring these fires under control.
“While no total fire ban will be announced tomorrow, most of the state is expected to face high fire danger.
‘It is important that you and your family have a plan and know what you will do if a fire threatens.’
As the cold front brings cool temperatures south, northern Australia will experience scorching conditions that could rival monthly records.
Temperatures above 40 degrees Celsius have been forecast in several cities, with Mount Isa and Longreach set to experience their hottest October days on record.
Darwin will top out at 34 degrees Celsius on Tuesday, alongside cloudy conditions, which will continue into the weekend.
Conditions in Perth are also expected to be warm and sunny, with a high of 28 degrees Celsius and winds decreasing in the afternoon.
On Monday evening, the NSW Rural Fire Service warned of ’62 fires across the state, 24 of which are not yet under control’ (pictured, North Coast fire)