Australia Weather News

Heavy sea fog has engulfed Sydney's eastern suburbs and reduced visibility at the city's most popular beaches.

Despite a sunny forecast across most of the city, Coogee and Bondi beaches spent much of the Monday under a thick layer of smoky fog.

The fog had also reportedly rolled into Gordon's Bay and encroached over Waverly Cemetery in Bronte.

The fog moved through the mainland early on Monday afternoon and swept over Circular Quay, covering the Harbour Bridge and the Opera House.

Bureau of Meteorology (BOM) forecaster David Wilkie said the weather phenomenon was associated with a weak southerly change and humid air conditions.

"In Sydney, we've had some very humid days over the last week or so," Mr Wilkie said.

"Typically those kind of conditions we see more regularly in February ... this period of increased [fog] is a little early in the season."

Unlike regular fog, sea fog does not just hang around for the morning.

"It's not likely to dissipate quickly with the sun," Mr Wilkie said.

"Obviously it's something that's persisting even though we have daytime temperatures that are quite warm."

He said sea fog like Monday's typically occurs in Sydney about once or twice a year.

"It's quite an amazing thing to see, if people have time they can go down to the beach and check it out," he said.