Climate Change Chart of Palermo, Italy

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +0.64 °C compared with the earlier reference period; this is an unweighted mean of monthly means, not a day-weighted annual average or a measure of daytime highs. The month-to-month differences were not uniform: December had the largest monthly increase, at +2.90 °C, while May had the largest monthly decrease, at -1.48 °C. These are comparisons of period averages for the named months, not evidence of a continuous change between the periods.

Changes in rainfall

Mean daily rainfall, rather than monthly rainfall totals, was higher on an unweighted average across calendar months by +0.53 mm/day in the more recent period. That overall mean difference masks contrasting monthly results: the largest increase was in November, with a difference of +1.51 mm/day, whereas December recorded the largest decrease, at -0.25 mm/day. These figures describe differences between reference-period averages and do not imply the same change in every month or on every day.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months had a difference of -0.31 hours/day in the more recent period, an unweighted comparison of monthly means rather than a day-weighted annual figure. The monthly pattern differed from that overall decrease: April had the largest decrease, at -0.80 hours/day, while December showed the largest increase, with a difference of +0.19 hours/day. The monthly extrema describe period averages and do not establish a continuous trend or a change in every individual month.

Changes in snowfall

Mean daily snowfall also differed between the reference periods. Averaged across calendar months, the unweighted mean difference was +0.05 mm/day; this comparison concerns daily amounts, not monthly totals. The largest monthly increase occurred in January, with a difference of +0.46 mm/day, while the largest decrease was in March, at -0.06 mm/day. These period-average differences do not indicate that the same pattern applied on every day or throughout each named month.