A cold snap to hit South Australia this weekend has prompted a rare cold weather health warning.
The weather bureau says Adelaide will have a top of just 12 degrees on Saturday with heavy showers and rising winds from an intense low pressure system.
Snow showers are also possible for parts of the Flinders and Mt Lofty ranges.
SA Health chief medical officer Paddy Phillips says in those conditions hypothermia is a real and significant health risk.
"The very old and very young, and those who are frail are at particular risk," Professor Phillips said.
"Some people may have a reluctance to use heaters because of the cost, but it's important that they consider their health during times of extreme cold."
The State Emergency Service (SES) has urged home owners and motorists to take care over the weekend with the wintery weather making driving conditions dangerous and increasing the risk of localised flooding.
"There may be a lot of water, ice, mud and debris such as fallen trees and branches on the roads, particularly in the Mt Lofty Ranges, the Fleurieu Peninsula and the mid North regions," SES acting chief officer Dermot Barry said.
Meanwhile, the icy blast from the Antarctic is about to sweep southern Queensland, bringing chilly temperatures, frosty winds and even snow.
Temperatures in Brisbane are set to dip up to five degrees below the July average and snow flakes are expected to fall at Eukey near the NSW border.
The effects of the icy blast will be felt from Sunday and temperatures are expected to remain chilly until Friday.
Bureau of Meteorology senior forecaster Brett Harrison said snow was expected to fall on upper parts of the Granite Belt, most likely at Eukey.
"There's a pretty good chance of seeing snow, particularly on Sunday morning," he told AAP.
Brisbane is set to shiver through its coldest day of the year on Monday, with a maximum of 15C and minimum of 6C forecast.
The maximum is five degrees below the July average, and the windy conditions will make temperatures feel even colder, Mr Harrison said.
He said the icy blast was due to cold air coming all the way up from the Southern Ocean.
"We've got a low pressure system that's going to develop around Victoria and it's going to push all of that cold air throughout the interior of NSW and into Queensland," he said.
Before the cold snap hits, thunderstorms are expected to hit parts of southern Queensland.
Storms are forecast for the Darling Downs on Friday and could extend into Brisbane on Saturday.
