More than 1000 firefighters worked into the night and on Thursday as they battled more than 80 fires from the far south coast to near the Queensland border.

NSW Rural Fire Service spokesman Ben Shepherd said 30 of the blazes were yet to be contained by Thursday afternoon despite more favourable conditions.

Temperatures peaked in the low-mid 20s in Sydney and surrounds, while the weather was cooler with scattered showers on the south coast.

But hot conditions continued in the state's north, including peaks in the mid-30s as a number of grass and bush fires burned in the region.

A strong wind warning was also in place for much of the NSW coast.

Mr Shepherd said the dangers were expected to subside in the coming days, giving firefighters the chance to control existing fires and complete more hazard-reduction burning.

"We're still seeing gusty winds in parts of NSW ... any fires in the landscape can be problematic, so we're trying to get on top of them," he told Sydney radio 2GB.

"As we move closer to the weekend, those winds will start to die down (and) we'll start to assess the opportunity there to potentially do some hazard-reduction work."

Firefighters have been racing to catch up on a backlog of planned burning, much of which was postponed earlier in the year due to widespread rain.

The recent drop in temperatures has come after the state sweated for days with maximum temperatures 10C to 15C above the September average.

A total fire ban remained in place on Thursday for the NSW northwestern region, which includes the Moree Plains, Narrabri, Walgett and Warrumbungle council areas.

Fire danger ratings were also high in the far north coast, New England, Greater Hunter, northern slopes and upper central west plains regions.

Premier Chris Minns on Wednesday said officials were worried about the prospect of a "horror" summer after four days of temperatures above 30C in early spring.

Australian Associated Press