The Bureau of Meteorology warns temperatures at ground level can be many degrees lower than those recorded by standard weather stations, especially in calm conditions with very clear skies.

The forecast is for frosts with temperatures down to -2 degrees for Tuesday morning in parts of the south-west, Mallee, Wimmera, North Central, North East, Central and West and South Gippsland forecast districts

Today across the south-west will be partly cloudy, with light winds and no chance of rain.

Warrnambool is expecting a top of 14 degrees, Hamilton 13, Colac 13, Ararat 13, Casterton 14, Mortlake 14, Heywood 14, Portland 13, Port Fairy 13, Terang 13 and Camperdown 12.

There's a frost warning for the south-west and much of Victoria.

A high pressure system crossing waters south of the Bight will move across Bass Strait today, reaching the Tasman Sea on Wednesday.

The next cold front and associated trough will approach western Victoria Thursday and will cross all but the far east of the state on Friday.

For the next couple of days Warrnambool is expecting fine days with tops of 17 and 20 for Wednesday and Thursday and 18 on Friday before showers set in. Saturday is going to only be a top of 12 for the Hampden league grand finals.

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