Climate Change Chart of Douglas, Isle of Man

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +0.73 °C in the more recent period. This is an unweighted comparison of monthly means, not a day-weighted annual average, and it does not mean that every month was warmer. The largest monthly increase was in June, at +1.89 °C; by contrast, November had the largest decrease, a difference of -0.10 °C. These are changes in monthly mean temperature, not daytime maximum temperatures.

Changes in rainfall

Mean daily rainfall, averaged across calendar months, had a difference of +0.81 mm/day compared with the earlier reference period. This unweighted mean describes the aggregate of monthly means rather than a day-weighted annual average, and it need not apply to each month individually. The largest monthly increase occurred in November, with a difference of +1.36 mm/day, while April recorded the largest decrease, a difference of -0.11 mm/day. These figures describe mean daily amounts, not monthly rainfall totals.

Changes in sunshine duration

Across calendar months, mean daily sunshine duration had a difference of -0.32 hours/day in the more recent period; this is an unweighted mean of monthly means, not a day-weighted annual figure, and does not imply the same change in every month. The largest decrease was in May, at -0.81 hours/day. In comparison, February / April shared the largest monthly increase, with a difference of +0.11 hours/day. These values concern mean daily sunshine hours.

Changes in snowfall

The mean daily snowfall difference, averaged across calendar months, was -0.01 mm/day. This small aggregate decrease does not mean snowfall was absent, nor does it establish the direction of change in every month. Monthly differences varied: January had the largest decrease, a difference of -2.12 mm/day, while March had the largest increase, at +1.24 mm/day. These are mean daily amounts, not monthly snowfall totals.