Thick fog is causing delays for flights in and out of Sydney Airport.

Passengers are urged to check with their airline to see if their trip is impacted.

Virgin Australia has advised some smaller flights will be delayed as air traffic controllers wait for the mist to lift.

Fog in Sydney is impacting flights in and out of Sydney Airport. Please check the flight status page for the latest info on your Virgin Australia flight: https://t.co/m479B0nZMc

— Virgin Australia (@VirginAustralia) October 18, 2018

The fog is expected to begin clearing after 9am, with a sunny afternoon forecast – tops of 26 degrees in the city and 31 in the west.

Weatherzone Meteorologist Brett Dutchkey has told Macquarie National News it will hang around in some areas.

“Still patches of some very thick fog. Most of those are in the south-west of the city but also in very sheltered valleys that we have around the city.”

These photos are taken from the exact same spot on our rooftop.

Fair to say it’s a bit foggy this morning…#SydWeather #Fog pic.twitter.com/T7cqf4vmCM

— 2GB 873 (@2GB873) October 18, 2018