Mandurah is tipped for a scorching 39 degrees on Saturday, potentially the highest November temperature on record.
The current record temperature for the month in Mandurah is 39.3 degrees on November 10, 1982.
The Bureau of Meteorology has already issued severe to extreme fire danger ratings across the State, with high temperatures, strong winds and dry conditions forecast.
The last severe fire danger rating in Perth was in January this year.
The UV Index is also at extreme, tipped to reach 11 in Mandurah between 8.10am and 3.50pm.
The warm weather will be short lived, however, with a Sunday forecast for a maximum of 23.