Footage posted to Facebook shows the inundated city streets, as well as people wading and cars driving slowly through floodwater.
The floods happened in a city that usually gets just 2.5 inches of rain a year.
The Saudi Gazette reported all schools and universities were closed due to the adverse weather.
There were flight delays at King Abdulaziz International Airport, Saudi Press Agency said. Credit: Jamal Ali Bin Ayed via Storyful