Tomorrow's race meeting at Ascot has been cancelled and health authorities are warning West Australians to stay cool and take care of the elderly ahead of blistering temperatures forecast for the weekend.
The Weather Bureau yesterday revised its weekend forecast, predicting a 44C maximum tomorrow and 39C on Sunday.
The hottest January day in Perth was on January 31, 1991, when the mercury hit 45.8C and the hottest day on record came in the same summer when the temperature rose to 46.2C on February 23.
The Australian Medical Association warned heat and humidity were responsible for more deaths than any other weather conditions and it advised people to familiarise themselves with the symptoms of heat exhaustion.
AMA WA president Richard Choong advised avoiding long stints in the sun, limiting exercising and being mindful of elderly neighbours and relatives.
"Heat exhaustion is a silent killer, so it is important to remain aware of the impact of high temperatures, especially on the young and elderly," Dr Choong said. Symptoms include increased heart rate, vomiting, dizziness, confusion, headaches, nausea and cramps.
Perth Racing this morning said the Ascot meeting will be postponed.
Racing and Wagering WA has reschedule the meeting to Sunday.
Perth Racing said the club would provide free entry to racegoers on Sunday.
Surf Life Saving WA is expecting thousands will descend on beaches at the weekend.
Lifesavers have urged beachgoers to take extra care on the coast - swim between the flags, keep hydrated and avoid drinking alcohol before entering the water.
The WA Health Department has warned pool and spa owners to ensure water is properly treated and maintained to avoid amoebic meningitis.
WA Environmental Health acting director Richard Theobald said the rare but potentially fatal disease could be contracted when recreational water contaminated with the amoeba bug entered the nose. "Amoeba thrive in warm water temperatures between 28C and 40C," he said.
He urged pool and spa owners to monitor chlorine levels closely and change the water in wading pools after each use.
St John Ambulance warned parents against leaving young children in parked cars.
WA acting operations manager Angela Wright said temperatures in cars could soar to fatal levels within minutes.
"If you see a child locked inside a car in need of medical assistance, call triple-0 immediately," she said.