Main Roads has issued the warning along with advice for motorists this morning.
The fog is expected to be worst between Thomas Road and Mortimer Road in both directions.
Motorists are urged to turn on headlights and keep a safe breaking distance between other cars.
Extra travel time should also be taking into account due to reduced visibility.
Cooloongup man accused of historical child sex offences dies just weeks before trial
A Cooloongup man accused of dozens of historical child sex offences has died just weeks before he was due to stand trial.
Boat owners urged to make safety a priority this Easter
Boat owners are being urged to make safety their priority this Easter and carry the required and recommended safety equipment including their Recreational Skipper’s Ticket (RST).
Mundijong man accused of attempting to procure children overseas for sexual activity
A Mundijong man is behind bars after allegedly attempting to procure children from the Philippines for sexual activity.
PM Anthony Albanese to address nation
Prime Minister Anthony Albanese will make a special address to the nation later today.
Mandurah teacher who raped student to remain on bail
A Mandurah teacher who raped a student and gave birth to his child will remain on bail for several months in order to undergo a psychiatric assessment.
Man charged after allegedly exposing himself to girl on Transperth bus in Lakelands
Child Abuse Squad detectives have charged a 31-year-old man over an alleged disturbing incident onboard a Transperth bus in Lakelands.
Fire rips through Golden Bay home
A fire has torn through a home in Golden Bay.
Firefighters battle bushfire near Nambeelup
Firefighters have spent the night battling a bushfire near Nambeelup.
Alcoa Children's Festival cancelled due to severe weather
The annual Alcoa Children's Festival scheduled for Saturday, March 28 has been cancelled due to extreme weather.