Tuesday was Australia's hottest day on record, according to preliminary Bureau of Meteorology data.
The Bureau of Meteorology recorded the average maximum across the nation as 40.9 degrees, beating the previous record of 40.3 degrees from January 7, 2013.
A spokesperson for the Bureau said temperatures tipped over 45 degrees through much of the nation's interior Tuesaday, news.com.au reports.
"This hot air mass is so extensive, the preliminary figures show that Tuesday was the hottest day on record in Australia, beating out the previous record from 2013 and this heat will only intensify," she said.
She said southern and Central Australia will be 8 to 16 degrees above average over the next few days.
A weak front will bring slightly cooler conditions to the far southern coast but the continued will maintain dangerous conditions in South Australia, with very high to extreme fire dangers forecast for northeast Victoria, NSW and the ACT.
Smoke will become a significant issue for populated areas in NSW and the ACT.
HOW'S THE REST OF THE WEEK LOOKING?
The BOM has said that "maximums across the board will be exceptional" for this time of year.
This searing heat is pretty much a fact of life in Central Australia right now. In Alice Springs it is forecast to top out above 45C for at least the next seven days.
Towards the coast the heat will come in pulses, with peaks Wednesday, Friday and Saturday depending on where you are.
Starting in Perth, Wednesday has seen 35C highs with an expected dip to the mid-twenties over the next couple of days, then it's back up into the mid-thirties on Saturday.
Adelaide has seen several consecutive days of absolutely scorching 40C-plus highs, and is tipped for 44C on Friday. That will be followed by a big dip to 25C on the weekend.
Renmark, in the Riverland, could reach 48C.
Melbourne can usually expect around 25C on an average December day. Not this week. The city saw a peak of 40C yesterday, and will reach 41C on Friday.
Mildura is looking at 47C on Friday, while Bendigo will settle around between 42 and 44C this week.
Hobart is expected to hit 33C on Friday, with more average conditions on the weekend.
Being inland, Canberra can expect all of the heat and little of the relief this week. Up to 37C yesterday, 41C today and then 39C on Friday.
On Saturday, Canberra could top out at 43C and nearby bushfires could lead to smoke haze. It could be the city's hottest day ever.
Sydney will see a relatively mild 27C on Wednesday and then 35C on Thursday with windy conditions fanning flames to the city's west and north west.
Down to 26C on Friday and then zooming back up to 37C on Saturday. The cool change will come on Sunday.
As ever, even hotter in the city's west. Penrith will reach 44C today, down to 33C on Friday and then a sizzling 46C which will only help those fires.
Brisbane is expected to hover around 30-33C for the rest of the week with a maximum of 35C on Sunday.
In the Top End, 35-36C for the foreseeable future with possible afternoon storms and a smattering of rain.
HEAT AND SURF WARNING
Surf Life Saving NSW has issued a warning ahead of extreme heat conditions over the next few days.
With soaring temperatures and school holidays expected to result in a big spike in beach visitations, surf lifesavers are urging people to play it safe on our beaches and waterways.
The tragic death of a man in the water off Terrigal beach last night has renewed the calls for people to exercise caution while trying to cool off and beat the heat.
Emergency services were called when a man was spotted waving and yelling for help just after 6pm last night.
He was pulled from the water and CPR attempts were made however the man was unable to be revived.
"We want everyone to have a safe and happy Christmas break and we want to avoid last year's terrible summer drowning toll," said Director of Lifesaving, Joel Wiseman.
"With a heatwave on the way, heat exhaustion is a very real risk and we would urge everyone to ensure that they are drinking plenty of water, reapplying sunscreen regularly, and stay out of the sun during the hottest parts of the day."
"If you become distressed we advise seeking treatment immediately from a lifesaver or lifeguard and watch out for older people and children in particular," said Joel Wiseman.
"Leading into Christmas and the New Year, we have a very simple message. Enjoy the water but do so safely by swimming at a patrolled location, wear a lifejacket if boating or rock fishing and always supervise children around water."
Surf conditions over the next few days are expected to be moderate with waves around 3 to 4 feet.
"Even benign surf conditions should not be underestimated," said Joel Wiseman. "Hazards such as rip currents are present at beaches most of the time and are the number one cause of coastal drownings each year."