Boaties have been advised to take care as a rare afternoon fog sweeps across Sydney’s coastline.
The unusual sight of low cloud is thanks to a moist air mass and weak winds, following a weekend of rain.
It brought reduced visibility along beaches mostly in the east but light winds pushed the fog along the coast throughout the day.
Sutherland Shire Lifeguards posted on Instagram around 3pm that “beaches are still open but may close if visibility decreases further”.
Bureau of Meteorology 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 today'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.
Monday reached a top of 29 degrees. There is the chance of a possible shower on Tuesday, but it will still remain quite warm, at about 25 degrees.
