THE hottest week this early in the season in six years is commencing over parts of South Australia and Victoria with maximum temperatures tipped to run as much as 10 degrees above average.
Inland areas of SA, Victoria and NSW are likely to average maximum temperatures in the high thirties from Monday to Sunday.
Places such as Adelaide, Mildura and Hamilton and many in between are forecast to have their hottest week this early in the season since November 2009 when a record early-season heat wave affected much of the region.
For the week from Monday to Sunday, maximum temperatures should average about 35 degrees in Adelaide, 39 in Mildura and 32 in Hamilton.
Meanwhile far western NSW and far northern South Australia, including Wilcannia, Oodnadatta and Marree should average a maximum of near 40 degrees for the week.
The area which should have days run as much as 10 degrees above the December norm is Ballarat which should average 32.5 degrees.
This sort of heat spell is more typical of January and February and is unusual this early in the season.
The last time Ballarat had a hotter week this early in the season was in 2002 when it averaged 33.6 degrees.
The source of this heat is the WA Pilbara which is heating up three-to-four degrees above average for this time of year with help sunnier-than-normal skies and warmer-than-normal seas nearby.
Cold fronts are also being held a long way south by a jetstream, encouraging heat to spread across central and southern Australia with the movement of a broad low pressure trough.
Thankfully for those who do not cope with hot spells such as this, nearly all evenings will provide some cooling relief under mostly clear skies.
And for those on the coast and in Tasmania it will be much more comfortable due to sea breezes.
The heat wave should come to an end late next weekend or early the following week with the arrival of a strong cold front.
However, nights will become uncomfortably warm next weekend just ahead of the cooler change.