The picture below shows the extremes of temperature that Australia has had to deal with recently. Note the cluster of high temperature in Victoria (scene of bushfires), the cluster of low temperature in northern Queensland (scene of flooding) and the temperature in Adelaide (scene of arson attacks thankfully put out before they became as dangerous as the Victorian bushfires).
For those who track their local temperatures using the Celsius scale, 40 degrees is a daunting number. In early February 2009, residents of southeastern Australia were cringing at their weather forecasts, as predictions of temperatures above 40 degrees Celsius (104 degrees Fahrenheit) meant that a blistering heat wave was continuing.
The Australian Bureau of Meteorology (BOM) called this heat wave “exceptional,” not only for the high temperatures but for their duration. One-day records were broken in multiple cities, with temperatures in the mid-40s. In Kyancutta, South Australia, the temperature reached 48.2 degrees Celsius (118.8 degrees Fahrenheit). Many places also set records for the number of consecutive days with record-breaking heat.
Nighttime temperatures broke records, too. In their special statement on the heat wave, the BOM wrote, “On the morning of 29 January, an exceptional event also occurred in the northern suburbs of Adelaide around 3 a.m., when strong north-westerly winds mixed hot air aloft to the surface. At RAAF Edinburgh [a regional airport], the temperature rose to 41.7°C at 3:04 a.m. Such an event appears to be without known precedent in southern Australia.
Trust me, we who had to deal with this heatwave can attest to how draining it can be of body resources.
Thus, daytime land surface temperature is often much higher than the air temperature that is included in the daily weather report—a fact that anyone who has walked barefoot across a parking lot on a summer afternoon could verify.