Climate Change Chart of Mecca, Saudi Arabia

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +2.50 °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 maximum temperatures. The largest monthly increase occurred in July, with a difference of +3.16 °C. That identifies the strongest increase among the reported monthly changes, rather than indicating that every month warmed by the same amount.

Changes in rainfall

Mean daily rainfall, rather than monthly rainfall totals, was lower on average across calendar months: the difference was -0.15 mm/day. This unweighted mean of monthly differences summarizes the comparison across the calendar months, but does not imply that rainfall declined in every month. The largest monthly decrease was in July, with a difference of -0.54 mm/day; in contrast, January had the largest monthly increase, a difference of +0.18 mm/day. These contrasting monthly changes show why the overall mean should not be read as a uniform month-by-month pattern.

Changes in sunshine duration

Mean daily sunshine duration had an average difference of -0.27 hours/day across calendar months. This is an unweighted summary of monthly means, not a day-weighted annual figure, and it does not mean the decrease applied equally to every month. The largest monthly decrease occurred in June, with a difference of -0.53 hours/day. The largest monthly increase was in March, where the difference was +0.03 hours/day—a contrasting monthly result that qualifies the overall average. These figures describe differences in mean daily sunshine hours, not the number of sunny days.