NSW is set to endure another stint of steaming hot weather, with authorities particularly worried about the growing risk of grass fires in inland areas of the state.

Parts of Sydney – including the city – broke the 40 degree barrier for a second straight day on Sunday after swathes of western NSW, South Australia and northern Victoria baked through even higher Saturday temperatures approaching 45 degrees.

On Sunday, the mercury pushed past 40 degrees in many Sydney suburbs, including Penrith, Canterbury, Bankstown and Holsworthy.

Observatory Hill recorded its first consecutive 40-degree November days on record.

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Temperatures in Newcastle and across the Hunter were also well in excess of 40 degrees, hitting 41.9 on Sunday at Cessnock Airport.

A gusty southerly arrived late on Sunday afternoon, quickly dropping temperatures by more than 10 degrees in many place, including Sydney.

An overnight minimum of 18 degrees was forecast for the city, about 7 degrees cooler than Observatory Hill’s record November minimum of 25.3 degree on Sunday morning.

The southerly change has brought a brief respite from the warmer weather for most of NSW, but sweltering weather is forecast to return from Tuesday. This would be particularly acute in NSW’s inland regions.

South-east and southern Queensland were also forecast to experience elevated temperatures from Monday, with no respite until at least Thursday.

Gundawindi, on the Queensland-NSW border, was expecting 45 degrees on Monday. Birdsville, in Queensland’s south-west, was shooting for 47 after enduring a minimum of 33.2 degrees on Saturday night.

Roseberth Station grazier Geoff Morton said there was no denying that it had been a hot week.

“Today will be our third day in a row of 47 degrees and for the past 10 days we’ve been [above] 45 degrees, so it is an extended heatwave and it’s not usual for November that’s for sure,” he said.

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On Sunday, RFS crews battled more than 60 bush and grass fires across NSW, including blazes in the Blue Mountains and Kenthurst and a fire that damaged a home in the western Sydney suburb of Northmead.

RFS Commissioner Rob Rogers said the Northmead fire was one of many blazes that “didn’t have apparent natural cause”.

“That’s one that would be considered suspicious and is under investigation by fire and rescue investigators,” he said on Monday.

There were total fire bans for NSW’s northern slopes and north-western districts on Monday .

Mr Rogers said Tuesday could be a tough day for firefighters in inland NSW.

“Coastal areas should still have a bit of a coastal sea breeze effect but nonetheless it’s going to be really hot,” he said.

“West of the ranges, it’s going to be very hot, dry, strong north-westerly winds, very low humidity. The sort of conditions we saw on the weekend are certainly going to be replicated from the southern part of the state all the way to the northern border, mostly inland.”

Mr Rogers also warned that rainfall across NSW in 2020 had caused significant grass growth, adding to the bushfire risk.

“There was no grass growing west of the ranges in the past few years because of the drought. Now there’s significant growth, probably more growth than we’ve seen in a couple of decades. That concerns us as that starts to dry off,” he said.

RFS Deputy Commissioner Peter McKechnie said there were three fires across the state that not under control, while Monday’s milder conditions would help with the remaining blazes.

“Whilst we still have 50 fires burning, there’s only three of them that are not contained and we’re quite confident of getting containment on them today,” he told the ABC.

Last summer’s bushfires destroyed 2476 homes and killed 26 people in NSW.

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Meanwhile, Endeavour Energy said 2100 customers remained without power after Sunday’s strong winds. More than 100,000 homes and businesses lost power in NSW on Sunday.

“We remain confident on having safely restored power to all customers this afternoon,” the company said.

-with AAP