Sydney is set for a warm and humid week of above-average and possibly record temperatures, with tops of about 30 degrees forecast across the city.

Monday will be the warmest day, with sunny skies and predicted maximums of 31 degrees in the CBD and 35 degrees in the west.

Bathers enjoy the sunshine at Mahon Pool in Sydney's east on Sunday. Credit:James Alcock

The rest of the week will then remain relatively warm with a few cold patches, with temperatures expected to hover in the high 20s until the weekend.

Brett Dutschke, a meteorologist with Fairfax Media's Weatherzone, said the week on the whole would be warm and moderately humid, with temperatures that are "unusually warm for this time of the year".