The thick fog which blanketed much of Sydney has lifted but dozens of flights are still delayed after the morning's chaos.
The Bureau of Meteorology issued an alert about the dangerous conditions on Wednesday morning, with visibility in some areas down to 200 metres.
The bureau says clear conditions, light winds and high humidity from recent showers led to the foggy skies that blanketed Sydney's west about 2am and reached Sydney Airport by 5am.
The fog, which delayed at least 47 domestic flights and a dozen international flights in and out of Sydney in the morning, cleared by about 10.30am.
More than 20 domestic flights and at least three international flights in and out of Sydney are still delayed.
While there's a chance Sydneysiders could wake up to another foggy morning on Thursday, it isn't expected to be as thick, BOM forecaster Mohammed Nabi said.
"It doesn't look like it will be as extensive," he told AAP on Wednesday.
"It would be more likely in the west, which is quite common for autumn."
Twitter user Chris De Bonis described the fog as "next level" as he travelled over the Sydney Harbour Bridge in the early morning.
"I thought I was going into a scene of Blade Runner," he posted.
Australian Associated Press