Mandurah could be drenched with up to 60mm of rain in the coming days, according to the Bureau of Meteorology forecast.
The Bureau is predicting heavy rainfall across Sunday and Monday, with potential storms set to disrupt the weekend.
The forecast for Saturday remains mostly sunny with a top of 20 degrees and almost no chance of rain, but the approaching cold front looks set to hit on Sunday with most of the state set to be battered with rain.
Areas ranging between Exmouth in the north and Walpole in the south are set to be hit by as much as 40mm of rain on Sunday, with a potential 20mm following on Monday.
The wet weather, which follows on from flash flooding in WA's south earlier this week, looks set to ease by Tuesday.
Temperatures for the rainy days aren't expected to breach anywhere above 18 degrees.
Mandurah experienced its wettest July day ever in 2020, with the fifth day of the month producing a whopping 53mm of rain.
In total the city fell just short of its monthly average for July, however, with its 111mm just missing the 115mm average.