The Harbour City can expect daytime temperatures 3-7 degrees above the August norm of about 18 degrees over the coming week, the Bureau of Meteorology said.

The agency, though, backed off an earlier prediction that Sydney could get a top of 28 degrees next Wednesday and now rates 25 degrees the more likely maximum. Friday's top will be 23 degrees before conditions cool slightly for the weekend.

"A dominant high pressure system is sitting near Brisbane, and we're going to see a series of fronts, one after the other, each dropping south" of Sydney, Rob Sharpe, a meteorologist at Weatherzone said.

Southern Queensland and northern NSW could see the mercury nudge towards the mid-30s, bringing the potential for August heat records to come into play, Weatherzone said. "And that's only the middle of August, which is fairly impressive," Mr Sharpe said.

For those planning to toil in this Sunday's City2Surf run, sunscreen may come in handy. Sunny conditions are forecast, with temperatures likely to rise from a cool 10-degree overnight minimum to a top of 21 degrees.

Those wanting a dip in the sea to ease the pain can look forward to water temperatures of about 19-20 degrees.

Dry times roll on

Along with the mostly westerly winds, most of coastal NSW can expect the extended dry spell to last for at least another week.

Sydney had its driest July since 1995, with only 12.6 millimetres of rain - well short of the typically tally of almost 100 millimetres.

(See bureau chart below showing predicted rainfall for the next eight days.)

Alpine regions can expect more snow from the coming fronts next week but temperatures will also lead to some snow melt.

"The best conditions for skiing are behind us," Mr Sharpe said, referring to last weekend's "amazing" falls that brought more than a metre of snow to some resorts.

Still, there should be some "useful" falls to look forward to next week, he said.

Weatherzone is owned by Fairfax Media, publisher of this website.