Only Thursday looks likely to break from the run of relatively mild days with top temperatures five to six degrees above the July average of 16.4 degrees, the Bureau of Meteorology predicts. Even Thursday, though, will be on the mild side with 18 degrees tipped.

At this stage, Sunday's forecast top of 25 degrees would match a typical summer's day, and could challenge the July record maximum of 25.9 degrees set in 1990.

A range of other sites in the state, such as Bourke in the far north-west, may also nudge monthly records, said Tom Hough, a meteorologist with Weatherzone. Bourke's forecast top of 28 degrees is not far off its July record of 28.9 degrees.

"We have a warmer air mass moving in from Thursday and Friday," with the accompanying westerlies drawing on the building heat over the continent, Mr Hough said.

Sunday should also see a break from the chilly overnight temperatures under cloudy skies, with the bureau tipping a relatively balmy 14-degree minimum for that morning. Sydney's long-run average minimum for July is 8.1 degrees.

For those still eyeing the ski slopes, there is more good news - at least for the first part of this week.

"There's a few weak cold fronts that will brush up against the ranges," Mr Hough said. They should bring 5-10 centimetres of fresh snow to the main resorts.

That warmer air mass moving through later in the week, though, may bear less-favourable tidings including possible rain for the lower alpine reaches.

"The best time [for skiing] may be up to Wednesday" for this week at least, he said.

The snow resorts got off to a slow start this season as moisture-bearing cold fronts have been pushed further south by the dominant high-pressure ridge that has set up over southern Australia.

July looks like being another relatively dry month. June was the second-driest nationally on record, the bureau said.

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