Figure 1: Bar plot of observed temperature extremes for each Perth HW event.

Average Tmax conditions over the first three HW days (bar) and average Tmin conditions during the second and third of those days (white line). The colour of each bar shows the concurrent phase of El Niño Southern Oscillation during austral summer, based on a threshold of ± 0.5 °C for the Oceanic Niño Index [3-month running mean of SST anomalies in the Niño 3.4 region (5oN-5oS, 120o-170oW)].