Perth has broken two weather records after four days of searing temperatures across Western Australia.

The temperature hit 40.4 degrees on Saturday — the hottest November day since records began in 1897.

It was also the fourth consecutive day over 35 degrees which is only the second time it has happened in November. The last time was in 1933.

Bureau of Meteorology WA duty forecaster Darryl Vink said Perth broke the record in style.

"Basically there's a high in the bight, a very broad surface trough down the west coast, [and] a hot air mass over the state," he said.

"And the north-easterly winds have brought down that hot air over the west coast.

"It's the hottest November day since records began in 1897, and it's also the hottest spring day since 1897."

But Mr Vink said the stifling temperatures were not expected to last long, with a cool change on the way as early as Sunday.

"So there's a cooling trend essentially," he said.

"We're getting down to 29 [tomorrow] and essentially temperatures below 30 or the remainder of the week."

Perth weather forecast: