The city's run of record warmth has kept her from buying a heater, but as temperatures are expected to hit lows of 12 and 13 degrees over the weekend, she'll be rushing in to get her hands on one.

"It was difficult to get out of bed this morning, I can tell you that much. I ran into a hot shower," the 35-year-old from Bondi said.

"I was offered to buy a heater off a friend of a friend who was moving back in March, but at that time it was so warm, I said no. I was stupid: I should have bought it."

Retailers said that customers this year had delayed preparing for the colder months, with many expected to start buying in the next few days rather than early in April, which has been the trend in past years.

It's only when the cold really sets in, as it did with lows of 10 degrees on Friday morning, that Bing Lee Alexandria saleswoman Joey Trinh says people start to "pay attention".

"Customers are quite funny in regards to buying heaters. They don't get them until it feels cold," she said.

Kelly-Anne Petersen, owner of Sydney Heaters and Pizza Ovens, said that, while it's taken a little longer than usual to get winter heaters off their shelves, they've reaped the benefits of the unseasonable warmth with their summer stock.

"Because of the warmer weather, we've had a lot more outdoor kitchens, wood-fired pizza ovens and barbecues run out," she said.

"People get their quotes [for heaters] ready, but they want to hold off spending the money. Then as soon as it gets cold, they freak out and want their heaters yesterday."

The Central Tablelands took some of the brunt of the cold blast, with towns including Oberon and Blayney covered in a light blanket of snow that started coming down on Thursday evening.

However, Bureau of Meteorology forecaster Peter Zmijewski said residents should not expect it to last, with temperatures between 11 and 18 degrees on Saturday expected to melt the snow.

"There is a possibility of snow [down to] about 700 metres on the Central Tablelands today, but the chance is a medium chance," he said.

"Probably we will see just a little bit of a dusting of snow, if anything."

Sydney is expected to warm up with tops of 20 degrees in the city and 17 in the west on Saturday, but Ms Molander doubts that will stop others like her from rushing to the shops to buy a heater.

"I expect it will be packed. I'm not looking forward to going," she said.

Fire and Rescue NSW, who have seen a 10 per cent increase in the number of house fires during the winter months, are warning customers to take care when using heaters and other products such as electric blankets.

"People need to keep flammable materials at least a metre from their heaters, and make sure that they don't overload powerboards with things like heaters and electric blankets," said Fire and Rescue NSW Chief Superintendent Michael Morris.

Consumers are also urged to check that smoke alarms are in working order.

With Rachel Clun