Perth has posted its earliest 40-degree day in December on record as the city experiences a sweltering start to summer on the heels of a record-breaking November.
The temperature climbed to 41.6 degrees Celsius just after midday on Tuesday, eclipsing the previous record of 40.4C on December 5, 1977.
"We've got a slow-moving high pressure system sitting in the bight and it's directing very hot north-easterly air down towards the west coast," Bureau of Meteorology spokesman Neil Bennett said.
"And it won't just be Perth; right up and down the west coast we're going to see some very hot temperatures over the next few days."
Temperatures are forecast to far exceed Perth's December average of 29.1C for the rest of the working week.
Another hot blast before some weekend relief
Maximum temperatures above 35C are forecast each day until a milder change comes through on Saturday, when a trough that is hovering along the west coast moves inland, allowing cooler onshore winds to push through.
Friday is also expected to surpass the 40C mark, putting Perth on track to record its hottest first week of December since records began in 1897.
"There will be a little bit of relief for the west coast on Wednesday as a trough moves inland but it's not going to bring much relief because the trough will then push back offshore on Thursday and the heat will return with a vengeance," Mr Bennett said.
"It could be even hotter than today on Friday. It will depend very much on the timing of the sea breeze as to what the temperatures could get to."
Reprieve will come in the form of a cold front on Saturday which will see Perth's maximum drop into the high 20s.
"On Saturday there's a frontal system approaching from the south-west and that will really push cooler air in and we'll see a drop in temperatures," Mr Bennett said.
Perth's blistering start to summer comes on the back of a very warm November, which saw the city notch up a mean maximum temperature 2.4C above average.
It also smashed its record for the hottest ever November day when it hit 40.4C on November 16.
Suspicious bushfire forces evacuations in Perth's south
On Tuesday afternoon a bushfire forced residents to evacuate their homes in the town of Forrestdale in Perth's south-east.
The blaze triggered an emergency warning and burnt through 47 hectares of bushland.
About 100 firefighters and air bombers spent several hours trying to keep the fire away from homes and a nearby primary school.
Authorities are investigating the cause of the fire, which is thought to be suspicious.
Forrestdale Primary School will be shut on Wednesday.