The mercury dropped down to a frigid 1.3°C in Adelaide overnight, the city's lowest springtime temperature in 137 years of records.

Last night was also colder than all but one night of the 2024 winter, beaten only by July 3 when temps dipped to 0.6°C. 

Other South Australian locations also experienced the unseasonable September chill overnight, including:

• Cleve –0.4°C: which shivered through the coldest temp on record for the Eyre Peninsula town of around 1000 residents (in 67 years of records). Remarkably, it was the first ever subzero minimum in any month!
• Loxton –1.9°C: which endured the coldest spring night in 29 years for the Murray River town of around 4000 residents in the Riverland district. 
• Edithburg 0.1°C: The seaside town on the eastern side of the Yorke Peninsula had its lowest spring temperature on record – a remarkably low reading for a coastal location.
• Hopetoun Airport (Vic) –2.9°C: The coldest springtime temp in 13 years for the Mallee town and the coldest anywhere in Victoria overnight beyond the alpine weather stations.

Why so cold in mid-September?

As discussed on Monday in our story about Canberra's coldest springtime temperature on record (–6.9°C), a cold airmass with Antarctic origins swept over southeastern Australia over the weekend.

While the cold front ushered in a brief burst of rain, hail and snow (for elevated areas), the airmass rapidly dried out afterwards with most areas missing precipitation altogether – including much of SA.

As the system rushed off into the Tasman Sea, a large high pressure system then parked itself over eastern South Australia overnight.

The combination of cold dry air plus light (or no) winds – and an atmosphere that is already very dry after minimal recent rainfall – was the perfect set of ingredients for a very chilly night.

Minimum temps will rise in coming days as the next cold front approaches. That front will bring showers to the southeast of SA but only the hint of a light shower or two to inland areas where significant rainfall is much-needed.