Australia's Bureau of Meteorology is piloting a new product - a heat wave forecast. It's a new product that is based on a specific definition of heatwave conditions for Australia. This is: three days or more of high maximum and minimum temperatures that is unusual for that location, plus it takes into account conditions preceding the hot weather, allowing for whether people have acclimatised to the heat or not.
As I understand it, the same temperature over consecutive days in September might rate as a heat wave that wouldn't rate as one in February, because people would have been acclimatised to summer conditions in February. Not that we won't have heat waves in February. That's when we can get the worst of them. Just that the temperature would probably have to be consistently higher than it would have been in September, to be classed as a heat wave.
In the same way, what is considered a heat wave in Cairns might not be considered one in Melbourne, because Melbourne, despite being much further south of the equator, can get quite a bit hotter than Cairns.
We're heading for a heatwave over the next few days. I've animated the BoM charts below.
The heat wave maps will help service providers such as power companies, ambulance, hospitals etc, as well as ordinary people.
You can read more about the new product and its purpose here. And here is a 2013 technical report from CSIRO on heat waves, written by John Nairn and Robert Fawcett.