The mercury plummeted to minus three degrees overnight.
Early fog blanketed the city this morning, however, we can expect sun and a top of nine degrees to finish the day.
We can also expect some morning frost and light winds becoming southwesterly 15 to 20 km/h in the middle of the day.
Local police had a quiet night, but a busy morning, with almost a dozen cars sliding off roads in the region due to black ice.
Ballarat Police Sergeant Michael Watts said conditions were bad and motorists need to take care on roads.
Victoria Police issued a warning on their Twitter account this morning.
Fire crews attended a false alarm at Sunicrust Bakery on Lal Lal Street just after 5am on Saturday morning.
Ballarat City Fire senior station officer Mark Owen said the morning frost froze the alarm valve, triggering the alarm.
Crews also attended a car accident at 7am on the Gillies Street overpass at the Western Freeway.
Mr Owen issued a warning for motorists to take care on the roads as black ice is common on roads in the region.
Paramedics have had a busy morning attending to several jobs in the region.
Units attended a truck rollover on the Western Freeway near the Cartons Road overpass just after 7am.
Two men were treated at the scene for back injuries, however, were not transported to hospital.
Two people aged in their 70s were taken to Ballarat Health Services Base Hospital after they were involved in a single car accident at Elaine at 8.30am on the Midland Highway.
A male was treated for chest and arm injuries and a female was treated for chest and leg injuries.
They were transported to hospital in a serious but stable condition.
Ambulance Victoria spokesman John Mullen said paramedics tended to the pair while they were trapped in the vehicle.
Mr Mullen said paramedics had attended several jobs on their way to work after cars slid off the roads.
He said paramedics who were on their way to work came across a number of jobs and stopped to render assistance.
"People just have to slow down," he said.
"Motorists must drive to the conditions."
Ballarat services appear to be running on time with no delays reported on Twitter.