Adelaide has shivered through its coldest September morning in a century with several South Australian towns dipping below zero degrees Celsius.
Bureau of Meteorology senior forecaster Simon Timcke told ABC Radio Adelaide the city experienced 1.3C at 5:39am on Tuesday.
"In fact, that's the West Terrace site's lowest September minimum temperature on record," he said.
"Pretty significant because it's a very long record there, we've been measuring temperatures there for 100 years or so."
Frosty start to the morning at Tanunda. (Supplied: Sharyn Rosenzweig)
Adelaide's northern suburbs hit a low of -0.2C at Parafield on Tuesday morning, while Mount Lofty in the Adelaide Hills recorded 1.6C.
The southern suburbs was slightly warmer with 3.5C at Noarlunga.
Mr Timcke said a front late last week brought a cold air mass over parts of South Australia and along with it a string of chilly days.
"With the high pressure system coming in, we haven't really seen a movement of that air mass," he said.
"We have the very cold air over the top of us, we've had clear skies, light winds overnight — all the ingredients for a very cold morning."
Roseworthy, Clare and Loxton experienced temperatures below zero degrees. (ABC News: Bethanie Alderson)
The freezing temperatures in recent days have affected wine grape growers who say they have suffered crop losses due to unseasonable frost.
He said other parts of South Australia including the Murray Mallee, Mid North, Yorke and Eyre peninsulas recorded temperatures in the negatives.
"Renmark, Lameroo, Snowtown, Cummins, Loxton, Kadina, Wudinna, Roseworthy, Keith, Port Pirie, Yunta, Clare all below zero," he said.
"Renmark's been down to -1.9C, -1.8C at Lameroo, Snowtown, Cummins, Loxton.
"Pretty chilly morning so if people are finding it hard to get out of bed this morning, there's a very good reason for it."
But the chill is not here to stay as the high pressure system moves eastward, with Adelaide expected to warm up to 19C and most of the state staying dry.
Swimmers braved the cold at Henley Beach on Tuesday morning. (ABC: Bobby Macumber)
Mr Timcke said the only exception is a slight chance of showers in the lower South East districts and Kangaroo Island.
"Unusually with that cloud there, not so cold, some of those locations in the South East are some of the warmest places in the state," he said.
"Cape Jaffa, Robe, Mount Gambier all had minimum temperatures around 8 to 9C.
"The clouds persisting overnight stopped the temperatures dropping quite so low down there."
Despite the icy temperatures, swimmers still braved the cold to take a dip at Adelaide's surrounding beaches.
Mason, 19, swims weekly at Henley Beach and said he finds the water "nice and rewarding".
"Some mornings I'd tense up and it'll be an awkward penguin waddle but today will have to be a run in otherwise I'll back out," he said.