Cooler temperatures to bring welcome relief on Sunday

Australians can expect some relief from searing temperatures tomorrow in the nation's southeast, with the forecast set to simmer down from the 40-degree highs of recent days.

The Bureau of Meteorology has forecast a maximum of 29 for tomorrow, with a possibility of showers.

Sydney will remain slightly hotter with a forecast maximum of 30.

The searing heat is due to a tongue of hot air sweeping across the nation’s southern states, as a high pressure system moves out into the Tasman Sea.

High temperatures have extended through central Western Australia, South Australia, north-western Victoria and western New South Wales, with Adelaide and western Sydney the stand-outs.

Temperatures in Penrith, in western Sydney, rose to 40 degrees on Saturday. 

After most of Melbourne and the Australian Open suffered from intense heat on Friday, the city felt the effects of a cool change on Saturday, with temperatures hovering around 24 degrees. 

While the change will bring relief from the heat across southern Victoria, a shift in wind direction still poses a threat for any fires that are burning in the region.

Emergency services have also been bracing for fire conditions in multiple areas around Australia with warnings issued for parts of NSW, Victoria and South Australia.

As a slow-moving mass of hot air sweeps over NSW in the coming days, the mercury will continue to soar, elevating fire danger ratings.

Hot and dry conditions in the Greater Hunter, Southern Ranges, Central Ranges, Northern Slopes and North Western regions of NSW have seen the Rural Fire Service enact a severe fire danger warning in those parts.

A similar threat level is expected for the Mallee, Wimmera, North Central, South West and Central areas of Victoria which are also set for hot and dry conditions amid north-westerly winds.

In South Australia, winds of up to 45km/h are expected in the morning and the Country Fire Service has issued an extreme fire danger warning for the Mid North, Mount Lofty Ranges and Yorke Peninsula regions.

Queenslanders are being spared the heatwave for now. But it is set to move across the state's south-east early next week, with temperatures forecast to reach 34 degrees in Brisbane on Monday - the first day back for Queensland school students.

However, western Queensland has not been spared from the scorching temperatures gripping Australia's south-east, with Thargomindah and Birdsville exceeding 40 degrees on Saturday.