Thredbo, Mount Hotham, Perisher and Falls Creek recorded a few centimetres of snow overnight and residents woke to below freezing temperatures.

In Sydney, the long summer is over with Friday and Saturday set to be the two coldest days since October.

A spell of cold, wet and windy weather will bring temperatures around 17 degrees and gusts of up to 110km/h on the coast.

A weather warning for gale force winds and rough seas is in place for Sydney, Macquarie, Hunter, Illawarra, Batemans and Eden Coastal Waters regions.

Weatherzone meteorologist Rob Sharpe said a cold front had combined with an east coast low and was drawing up cold air from the south of Australia and pushing it through into NSW and Victoria.

While the ski season doesn't start until the Queen's Birthday weekend in June, Mr Sharpe said it was possible to get snow falls in the alpine regions during warmer months if a very strong cold front came through.

"During summer, it was snowing in the Victorian Alps while it was 42 degrees in Sydney – so it definitely does happen," he said.

Friday's falls at Thredbo and over the Snowy Mountains were the first properly recorded snowfalls in NSW this year.

Falls Creek posted pictures on their Facebook page showing a thin blanket of snow saying: "Impressive for April! 49 days to go."

The coldest spot in the state on Friday morning was Mount Hotham, where it was -3 degrees.

The worst of the cold, windy weather in Sydney is set to pass by Saturday afternoon, with warmer temperatures and lighter winds due on Sunday.

For the beginning of next week, showers are forecast to clear with the mercury rising to the mid-20s.