Climate Change Chart of San Juan, Puerto Rico

Overview of climate changes

Temperature changes

Across calendar months, the unweighted mean of monthly mean temperatures shows a difference of +0.79 °C compared with the earlier reference period; this summarizes the monthly means and is not a measure of daytime maximum temperatures or a continuous trend. The largest monthly increase in mean temperature occurred in June, with a difference of +1.04 °C. This identifies the largest increase, rather than describing every month.

Changes in rainfall

Averaged across calendar months, mean daily rainfall shows a difference of -0.45 mm/day. This is an unweighted summary of monthly means, not a change in monthly rainfall totals or a day-weighted annual average. The clearest monthly contrast in the supplied changes is in October, where mean daily rainfall had a difference of -1.58 mm/day. In contrast, March had the largest monthly increase, with a difference of +0.59 mm/day; these are monthly mean daily amounts, not totals.

Changes in sunshine duration

The unweighted mean difference in daily sunshine duration, averaged across calendar months, was -0.09 hours/day compared with the earlier reference period. It summarizes the monthly means rather than indicating that each month changed in the same way. The largest monthly decrease in mean daily sunshine was in November, with a difference of -0.40 hours/day. The largest increase was in May, at a difference of +0.25 hours/day, showing that the monthly changes were not uniform.