Perth is set to swelter in its hottest start to summer in nearly a decade with high temperatures forecast for much of the coming week.

Key points: The maximum temperature in Perth could climb as high as 40C in the coming days

The maximum temperature in Perth could climb as high as 40C in the coming days Weather forecasters say Perth has not seen such a hot start to summer in years

Weather forecasters say Perth has not seen such a hot start to summer in years It follows a very hot November in which a number of weather records were broken

The mercury is tipped to reach 35 degrees Celsius on Monday before climbing to 39C on Tuesday with a slight drop to 37C on Wednesday and 35C on Thursday.

Wednesday could reach up to 40C if an expected wind change does not occur until later in the afternoon.

Bureau of Meteorology (BOM) senior forecaster Pete Clegg described it as an unusual start to December.

"It's certainly a very hot start to summer," he said.

"Certainly not something that we've seen at least sort of in the order of eight or nine years — that we've had the three or four days of 35-plus in December.

"And it's very unusual to see it this early in December as well."

Flocks of people will be heading to Perth's beaches this week. ( Flickr: strangejourney )

Mr Clegg said a hot air mass in WA's north would move down the west coast over the coming week.

"So very similar to the sort of pattern where we had the 40.4C day back in November," he said.

"Wednesday the trough starts to move inland, so it's really going to depend on how quickly that moves in from the coast.

"At the moment we're going for a top of 37C. It'll get really hot very early in the day and if that timing of that wind change is just a little bit later, it could easily be another 39 or even a 40-degree day there."

More heat records set to fall

And while the bureau said it was still waiting for confirmation, it appeared Western Australia just experienced its hottest November on record.

A weekend of intense heat in WA in mid-November also saw 36 locations, including Perth, record their warmest November day on record.

Many WA locations experienced their hottest November day on record. ( ABC News: Andrew O'Connor )

Mr Clegg said high temperatures continued throughout the month and this could see records tumble.

"It does look like, for the mean temperature and also for the maximum temperature for WA it looks like it's going to be the hottest on record," Mr Clegg said.

"Up in the Pilbara they copped a little bit of thunderstorm activity which brought them a bit of rainfall quite late in the month of November, but otherwise through a lot of WA it was really dry as well.

"That comes off the back of us breaking records in August with highest temperatures on record as well, so I suppose it's been a bit of a trend for most of this year that we've been breaking those maximum temperature records."

The hot air mass is expected to shift by next Saturday, bringing cooler temperatures.

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