Climate Change Chart of Perth, Australia

Overview of climate changes

Changes in rainfall

Mean daily rainfall, rather than monthly rainfall totals, had an across-calendar-month average difference of +0.14 mm/day. This is an unweighted mean of the monthly averages, so it summarizes the overall monthly pattern without implying that rainfall increased in every month. The largest monthly increase occurred in March, with a difference of +0.89 mm/day; the largest monthly decrease was in June, at -1.39 mm/day. These month-specific changes show why the average should be read alongside the contrasting monthly shifts.

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +0.11 °C compared with the earlier reference period; this is an unweighted comparison of monthly means, not a day-weighted annual average or a measure of daytime highs. The month-specific differences were uneven: December had the largest monthly increase, at +1.31 °C, while April had the largest monthly decrease, at -0.77 °C. These extrema identify the strongest supplied changes in opposite directions, rather than describing every month's conditions.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months had a difference of -0.16 hours/day compared with the earlier period, an unweighted summary of the monthly means rather than a day-weighted annual figure. Monthly differences varied in direction: March recorded the largest decrease, at -0.59 hours/day, while June had the largest increase, at +0.31 hours/day. These are changes in mean daily sunshine hours for the specified months, not descriptions of every day within them.