(Climate Commission) – The length, extent, and severity of this heatwave are unprecedented since records began.
- This is the longest period ever for such persistently high temperatures.
- For seven days running, from 2–8 January 2013, the average daily maximum temperature for the whole of Australia was over 39 °C, easily breaking the previous record of four consecutive days over 39 °C.
- In fact, there have only been 21 days in 102 years where the average maximum temperature across Australia has exceeded 39 °C; eight of these days happened this summer (2–8 January and 11 January 2013).
The extreme heat followed an unusually very warm and dry period at the end of 2012, with below-average rainfall across much of Australia and a notably late start to the monsoon period (BoM, 2013a). The September-December 2012 period was the hottest ever. The average Australian maximum temperature was higher than for any other September- December period since records began in 1910.
Since mid-2012 much of Australia was drier than usual. The build-up of extreme heat in the southwest of Western Australia signalled the beginning of the first heatwave (Figure 5). Perth experienced seven consecutive days above 37 °C from 25–31 December, equalling a previous record (BoM, 2013a). Then a second heatwave brought record breaking heat on 8-10 January 2013. The central and southern interior suffered particularly extreme conditions, with Leonora recording the highest temperature in Western Australia during this event (BoM, 2013a).