Figure 3

(a) Relative frequency density (RFD) of % change in rainfall between the recent 20-year period average and the first 60-year period average, calculated by random re-sampling of individual years (with replacement) from the full historical period (120 years; 1901–2020) 10,000 times and computing the % difference each time. Black (thin) dashed vertical lines in (a) from left to right represent the 1st percentile and median of the observed resampled distribution. The observed % change for the 2001–2020 period relative to the mean of 1901–1960 is indicated with the heavy dashed vertical line in orange. This line (at -20.5%) indicates that the observed change is outside the bootstrapped distribution. (b) RFDs of area-averaged monthly rainfall through the cool season (May to October) for six different 20-year blocks from 1900–1919 through to 2001–2020 period shown as coloured lines (see legend in (b)). The RFD for the full early period (1900–2000) is also shown for comparison (solid black line). The vertical lines represent the median values of the distributions. The median values (mm month⁻¹) are shown in the parentheses in the legends. The horizontal segments indicate the 5th and 95th percentile confidence interval of the medians for each period, estimated using bootstrapping of monthly average rainfall for the period shown.