Wild weather caused havoc on the roads with flash flooding in Ross Creek and Smythesdale, trees down across roads throughout the region and winds of up to 100km/h overnight.

Bureau of Meteorology forecaster Stephen King said that it was likely Ballarat would receive a total of 40 to 50mm by the morning.

"There were gusts up to 74km/h in the afternoon and gusts of up to 100km/h overnight," he said.

"There's a low pressure system, which is in eastern Victoria now and moving out to the Tasman Sea."

Mr King said Ballarat had been hit by the strong wings and rain at the end of a low pressure system.

"Ballarat's average rainfall for August is 74mm," he said.

"You've already had 61mm to 9am yesterday, plus another 38mm, that takes us up to 89mm for August and we're only a third of the way through the month."

However, the rainfall is nowhere near Ballarat's wettest August on record, which was in 1909 when 167.1mm fell, including 72.1mm on one day.

Mr King said conditions would ease today, with some showers and winds.

"It should be becoming fine by Friday," he said.

Last night a Maryborough Police sergeant commented that he hadn't seen such a bad night in years.

"We need the rain but not all the damage the comes with it," he said.