Sydney residents are bracing for the coldest weekend in two years, with minimum temperatures set to plunge to single digits for the next four days.

It will be a chilly start to Saturday, with a minimum of 3 degrees in the city and 8 degrees on the coast, according to the Bureau of Meteorology.

Frost and fog in western Sydney. Credit:Nick Moir

But residents in Sydney's west are tipped to bear the brunt of the cold weather. Penrith residents can expect a shivery start to the day on Saturday with a minimum of 1 degree, before a slight rise to 2 degrees on Sunday morning.

Campbelltown will be the coldest part of the greater Sydney region over the weekend, with a minimum of 0 degrees expected for Saturday.