The mercury in Canberra plummeted to 0.3 of a degree overnight - the coldest December minimum on record.
The unseasonably chilly temperature was recorded at 5.44am, and by 6.45am the mercury was still only sitting at four degrees.
A duty forecaster from the Canberra office of the Bureau of Meteorology said the minimum this morning was the coldest Canberra has experienced in 75 years of records.
"A frontal system has moved up from the south bringing cold air with it," she said.
"It's what we call an air-mass change."
Warmer northerly winds are expected from Friday, which will raise temperatures heading towards the weekend.
The forecast for today is for sun and lights winds with a maximum temperature of 25 degrees.
By Saturday the temperature will be back up to 30 degrees.
This morning's cold weather follows a day of wild winds on Wednesday, that caused power blackouts to thousands of properties across the territory.
In a return to winter weather, wind gusts at Canberra Airport reached up to 64km/h at 1pm according to the Bureau of Meteorology, which released a severe wind warning for the region.
The ACT State Emergency Service received at least 33 calls for help during the day.
- with Larissa Nicholson