Climate Change Chart of Adamstown, Pitcairn

Overview of climate changes

Changes in rainfall

Averaged across calendar months, mean daily rainfall showed a difference of -0.24 mm/day. This is an unweighted mean of monthly mean daily amounts, not a day-weighted annual figure or a monthly rainfall total. The largest monthly decrease was in January, where mean daily rainfall had a difference of -2.17 mm/day compared with the earlier period. In contrast, September had the largest monthly increase, a difference of +0.72 mm/day. These are the reported monthly extremes and do not imply that rainfall moved in the same direction in every month.

Temperature changes

Averaged across calendar months, monthly mean temperature showed a difference of +0.38 °C compared with the earlier reference period; this is an unweighted mean of the monthly means, not a day-weighted annual average or a measure of daytime maximum temperatures. The largest monthly increase was in March, with a difference of +0.78 °C in the monthly mean. This identifies the strongest increase among the reported months, rather than describing the change in every month.

Changes in sunshine duration

Across calendar months, mean daily sunshine duration had an unweighted mean difference of -0.15 hours/day; this summarizes the monthly means rather than a day-weighted annual average. Monthly differences were not uniform: January recorded the largest increase in mean daily sunshine, at +0.35 hours/day, while the largest decrease was in October, at -0.72 hours/day. These extrema describe the monthly comparisons, not daily conditions throughout either period.