If you found yourself dusting off your jumpers this week, you probably weren't alone.

That's because Melbourne had its coolest end to January in 15 years, the Bureau of Meteorology says.

A lone fisherman braves the unseasonably cool summer weather at Port Melbourne. Credit:Salona Chithiray

And prospects of hitting the beach are not expected to improve, with top temperatures in the low 20s predicted through to next Friday.

Senior weather bureau climatologist Kevin Smith said the average maximum temperature at Melbourne Airport for the five days to Friday had been 22.6 degrees.