The Bureau of Meteorology has forecast the city will have a maximum of 26 degrees on Sunday and 28 degrees on Monday, with showers to linger on both days.

Rain is also expected in the city's west, after a run of 30-degree days on Thursday, Friday and Saturday.

Penrith will have a warmer New Year's Eve, with a maximum of 31 degrees, while a top of 35 degrees is expected on New Year's Day.

Angus McLean-Smith, a meteorologist with Fairfax Media's Weatherzone, said the showers would be intermittent.

"For the Sydney area, on Sunday - which is New Year's Eve - we can expect a few showers throughout the day. Obviously with showers, there's going to be a few clouds about as well," Mr McLean-Smith said.

"Those showers should clear up in the evening, so it should be clear around about 12 (midnight).

"Moving into Monday, it should remain clear in the morning. In the afternoon, more showers are expected."

Mr McLean-Smith said there is a chance of thunderstorms for Monday afternoon and night. Any rain that falls will not be "extensive", with a maximum of 5mm expected.

"Temperatures on the Monday look to be warm," he said.

Rain didn't dampen enthusiasm at North Cronulla Beach on Wednesday morning, with locals and joggers watching the sunrise break through the clouds.