Melbourne has woken up to its coldest day of the year so far, dropping down to 3 degrees shortly after 7.30am when the city was getting ready for work.

The last time it was this cold was late last August when the mercury plummeted to just 0.8 degrees, Bureau of Meteorology forecaster Peter Newham said.

Wednesday morning was just 0 degrees in Scoresby in the outer south-east of Melbourne, and 0.4 in Viewbank in the north-east.

Cloud cover kept Geelong comparatively toasty, with temperatures only dropping to 7.3 degrees overnight.