A cold snap has brought unseasonable weather for Australia's southern states over the start of summer.
Snow dusted the Australian Alps four days in a row last week while Hobart recorded its coldest December Day in 50 years.
People have particularly felt the chill in Melbourne and Sydney, which recorded the coldest mornings of 8.1C and 12.5C respectively, and December days have averaged more than 2C cooler than last year.
But a weather system due to move across the country this week is holding hope for a classic Christmas Day of cold cuts and backyard cricket under the sun.
So why does Sydney feel so cold right now?
Because cold air from the south has brought winter-like weather.
ABC meteorologist Tom Saunders described it as a "conveyer belt of cold southerlies", feeding bursts of polar air predominantly across Victoria, New South Wales and Tasmania.
Warm weather is yet to return with Melbourne residents waking to a minimum of 9C on Tuesday and Sydneysiders a minimum of 14C.
But it should warm in time for Christmas with the Bureau of Meteorology's senior forecaster Dean Narramore advising there will be a gradual return of average December temperatures throughout the week.
A system moving across central Australia will drag some northerly winds down through inland areas and eastern Australia.
"It's not until we get to Sunday that we finally see the heat rapidly build across much of southern and south-eastern Australia, just in time for Christmas," Mr Narramore said.
What is the weather forecast for Christmas Day?
Conditions are "looking sensational" right around the country, according to Mr Narramore.
Much of southern, eastern and western Australia should be warm to hot and sunny with lots of sunshine, and light winds.
Mr Narramore said the weather would be "beautiful for the barbie or the beach" in Perth, Adelaide and Melbourne where it's expected to be warm and sunny.
Hobart will be a little cooler with the chance of shower but still "fairly pleasant".
There should be an easing of that unseasonably cool weather for Sydney and Canberra by Christmas.
Brisbane is likely to be partly cloudy and there could be a stray shower further inland.
"Most should stay dry on the coast," Mr Narramore said.
The forecaster painted a different picture for the country's north with "almost-monsoonal" weather expected for Christmas Day.
Showers and possible thunderstorms are on the cards.
"Generally, right across the country, it's looking pretty good at this stage," Mr Narramore said.
How accurate are the Christmas forecasts?
Given Christmas is now less than a week away, forecasters have a pretty good idea of how the weather will play out.
Mr Saunders pointed out on Friday that there was an obvious reason BOM released a seven-day forecast and not a 10-day forecast — it's more reliable.
Mr Narramore said on Monday he was pretty confident the Christmas weather forecast should remain fine for the southern capitals.
That's because there's going to be a very large high pressure system over much of southern Australia, driving warm weather across the weekend.
"The temperatures might change a degree or two but generally we're looking at that warm, sunny weather," he said.
Forecasts for Queensland and the Northern Territory are slightly less reliable at this stage.
The position of a trough will determine how much wet weather Brisbane receives over the weekend.
Mr Narramore said while the weather can be chaotic and dynamic, most of the BOM's guidance was pretty accurate about four to five days out.
BOM issues seven-day forecasts for towns across the country but Mr Narramore said it's important to keep in mind that there's still room for changes across days five, six and seven — which at the moment includes Christmas Day.
"It's not until you get a bit closer in that five to seven day period that you get a consensus of what the weather systems are likely to do," he said.
"And once you get into that three-to-five-day period, we have a much better idea of the weather that is going to impact your part of the world."
Will it rain on New Year's Eve?
It's hard to know what the weather will be doing around the country on New Year's Eve, given what Mr Narramore has said about forecasting outside 10 days.
He said the BOM's guidance shows warm weather for the southern states should remain into at least early next week.
"Once we get into the middle of next week, it's a bit hard to say what will be going on with rain and storms in the north, and if they will come down or not," Mr Narramore said.
"But definitely Sunday, Monday and even Tuesday we will probably see that heat continuing and maybe even increase as we move into the middle of next week — particularly across southern and south-eastern parts of the country."
