Hottest March day on record for parts of NSW

Parts of New South Wales have smashed heat records to see the hottest March day ever.

Today's highest temperature recorded was 43.8C at Wilcannia Airport in the Central Darling Shire in the state's northwest.

The Bureau of Meteorology said Penrith, in Sydney's west, which had been forecast to reach 40C, got to 38.7C at 3.48pm.

Campelltown and Camden reached 39C, with Badgerys Creek the only Sydney suburb to officially pass 40C, reaching 40.2C at 3.28pm.

Richmond and Bankstown reached 38C.

The state's western districts sweltered, with temperatures above 42C in Bourke, Cobar and Brewarrina.

The Riverina also saw extreme heat with Griffith and Yanco both reaching 41C.

The Bureau of Meteorology said Sydney's four days of 30C in March was a record-breaking run, set back in 1878.

In its latest forecast on Sunday afternoon, the bureau said cooler conditions can be expected after the run of record March heat.

"Sunday was a day of record temperatures and elevated fire danger," the bureau's Dean Narramore said.

"A trough will move into South Australia on Monday with light showers on southern parts, spreading into Victoria and NSW at night."

Firefighters across both NSW and Victoria remain on alert as strong winds are still forecast on Sunday afternoon, with at least 30 fires still burning in NSW.

A fire at Craigs Road in Curraweela, in the Southern Tablelands, was being controlled but had burned through 3689 hectares, destroying property and livestock.

Victoria's Country Fire Authority says a bushfire at Lorne, east of Erskine Falls Road, is now at an advice level.

Temperatures in the state should hover about the low to mid-20s for the rest of the week.