Mortlake residents took to social media to report snowflakes falling in the town, about 50 kilometres inland of Warrnambool.

Macs Hotel barista Alex Cameron said he glanced out the hotel window and saw rain falling that seemed "more opaque than usual".

"I went outside to see whether it was sleet or whether it was snow, and it was snow for sure," Mr Cameron said.

"People were pretty energetic about it. I have lived for almost 10 years in Mortlake and never seen it."

The temperature in Mortlake dived to about three degrees Celsius at 8.30am.

Mortlake and District Historical Society president Kelvin Goodall said the society believed the last major snowfall in Mortlake was in 1981.

Bureau of Meteorology forecaster Miriam Bradbury said it was "very unusual" for snow to fall in Mortlake given it had an elevation of less than 300 metres above sea level.

"Our snow level is sitting around 600 to 700 metres, what that means is that anywhere above 600 metres we could see snow on the ground. We do see it at lower elevations but it doesn't stick around on the ground for too long," she said.

"I imagine some flurries in the air may be sitting on the ground for a few minutes but melting to puddles and slush pretty quickly."

She said heavy rain had fallen in the south-west overnight, including about 40 millimetres in Warrnambool.

"We had thick cloud with totals of 25 and 40 mm of rain in the south-west coast. Slightly less inland generally between 15 and 25 mm," Ms Bradbury said.

"There are still showers on the forecast for the rest of the day, we have probably seen the worst of the rainfall coming through."

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