Police and SES workers launched a search for the woman about 11:00pm last night, and she was found at 7:20am today in a marshy area of bushland.
She was safe and well but very cold and wet, police said, after the city was lashed by rain overnight.
She has been taken to Joondalup Health campus for a check up.
More rain is expected today along with the chance of a squally thunderstorm, with gusty winds and the possibility of hail.
Meanwhile a person died overnight after a rollover in Roelands, in the state’s South West.
The accident happened on Raymond Road, which had been closed to traffic at the Forrest and South West Highways.