Temperatures are dropping rapidly as a cold front surges across southeastern Australia, with the coldest air enveloping Tasmania and leaving our southernmost state with a heavy coating of snow to low levels this Tuesday.

This was the scene at the Mt Mawson public shelter, about two hours northwest of Hobart just before 10 am this Tuesday.

The shelter, located at the bottom of the Mt Mawson club-run (non-commercial) ski area, is situated at just under 1200 metres above sea level. Often, that's around the low extent of the snowline during a spring snowfall, but snow is forecast to fall as low as 300 metres in Tasmania today.

Temperature observations illustrating how cold it this Tuesday

Image: 850 hPa temperatures and mean sea level pressure for Australia at 10 am (AEST) on Tuesday, September 15, 2026. Source: Weatherzone.

The image above shows the cold air mass pushing northwards across Tasmania and the southeastern tip of the mainland as air circulates around the high pressure system located over the Great Australian Bight.

At 10:30 am (AEST), the coldest observed temperatures in three states included:

Tas

-1.2°C (with an apparent or "feels like" temperature of -13.3°C) at kunanyi/Mt Wellington above Hobart

Vic

2.1°C (with an apparent or "feels like" temperature of -5.7°C) at Mt William, the 1167m highest point of The Grampians in western Victoria's Wimmera region

NSW

4.6°C (with an apparent or "feels like" temperature of -5.4°C) at Thredbo Top Station

It's worth noting that the coldest air had not yet progressed to the mainland high country by Tuesday mid-morning, which is why Victoria's coldest reading at 10:30 am was at Mt William in the state's west, while Australia's highest weather station near the top of the Thredbo ski slopes was still several degrees above zero.

But the cold air is progressing north, albeit with limited moisture, which is why mainland snowfalls will be much lighter today than down south in Tasmania.

Why is it so cold in Tasmania and the southern mainland this Tuesday?

Image: Combined satellite and radar loop for southeastern Australia for the four hours until 10:30 am (AEST) on Tuesday, September 15, 2026. Source: Weatherzone.

The loop above shows a polar air mass starting to cross the southeast on Tuesday morning, with the bulk of the moisture (the green blobs) lashing western and central Tasmania.

As Weatherzone meteorologist Ben Domensino has previously explained, the classic speckled cloud pattern develops when cold polar air moves over a relatively warm body of water, creating atmospheric instability that generates a field of individual cumulus cloud cells separated by clear patches of sky.

Multiple wind warnings issued on Tuesday

As mentioned in our Monday story, strong winds are accompanying this icy blast, and while many of the strongest readings occurred during the northwesterlies that preceded the polar air mass, gusts again topped 100 km/h today at Maatsuyker Island on Tasmania's southwest tip.

Numerous strong wind warnings are in place, especially for coastal areas of Tasmania, Victoria and southern New South Wales, so please check the latest on the Weatherzone warnings page.