Sydneysiders could face showers and thunderstorms before they head down to the harbour, flick on the cricket or storm the shops on Boxing Day.
But it won't last long.
The Bureau of Meteorology has forecast "a mostly sunny day" with showers and storms clearing by mid morning.
The winds on Sydney Harbour are expected to pick up to 40 kilometres an hour [or 25 knots an hour in boat speak] as the starters gun fires for the Sydney to Hobart yacht race.
"They'll be going straight into the wind so it will be pretty choppy out there," said the Bureau of Meteorology's Jake Phillips.
"Southerly winds mean it's going to be hard for the boaties," concurred Weatherzone's Max Gonzalez.
For the rest of the city, the winds mean that temperatures will remain a pleasant 25 degrees for most of the day with a top of 30 degrees in the west.
The outlook does not look so good for the cricketers taking the field for the Boxing Day test in Melbourne.
They would be wise to pack their creamy sleeveless sweaters with a nippy low of 11 and not-so-summery top of 18 degrees predicted.
Early rain could delay the start of the match, but Weatherzone meteorologist Brett Dutschke said it was unlikely to be significant.
"The rain is most likely to clear after sunrise. There could be the odd spots around the place. I doubt that will lead to any delay for the start of the Test," he said.
