Climate Change Chart of Avarua, Cook Islands

Overview of climate changes

Temperature changes

Monthly mean temperatures were higher on average across calendar months in the more recent reference period, with a difference of +0.62 °C. This is an unweighted mean of monthly means, not a day-weighted annual average, and it describes the aggregate rather than every month; it also does not represent daytime maximum temperatures. The largest monthly increase was in June, at a difference of +0.93 °C. This identifies the strongest increase among the monthly means, not a general measure of daytime warmth.

Changes in rainfall

Mean daily rainfall decreased by a difference of -0.18 mm/day when averaged across calendar months in the more recent period. This unweighted comparison of monthly means is not a day-weighted annual average, and the overall mean difference should not be read as a decrease in every month. Monthly changes were not uniform: May had the largest increase, a difference of +1.33 mm/day, while November had the largest decrease, a difference of -2.43 mm/day. These figures describe mean daily rainfall, not monthly rainfall totals.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months was lower in the more recent period, with a difference of -0.12 hours/day. This is an unweighted mean of monthly means rather than a day-weighted annual average, so it summarizes the calendar-month averages and does not imply that sunshine decreased in every month. The largest monthly increase occurred in September, at a difference of +0.48 hours/day; the largest decrease occurred in December, at a difference of -0.37 hours/day. These are changes in mean daily sunshine hours for the named months, not totals over each month.