Climate Change Chart of Belfast, Great Britain

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +0.20 °C compared with the earlier reference period; this unweighted comparison of monthly means is not a day-weighted annual average or a measure of daytime maximum temperatures. The largest monthly increase was in January, at a difference of +0.61 °C, while the largest monthly decrease was in April, at a difference of -0.59 °C. These identify the strongest reported monthly changes, rather than describing every month's conditions.

Changes in rainfall

Mean daily rainfall, rather than monthly rainfall totals, averaged across calendar months had a difference of +0.47 mm/day in the more recent period. This is an unweighted comparison of monthly means, not a day-weighted annual average. The largest monthly increase was in December, with a difference of +1.03 mm/day; the largest monthly decrease was in April, with a difference of -0.25 mm/day. These monthly extremes show that the mean change across months does not describe the shift in every month.

Changes in sunshine duration

For mean daily sunshine duration, the unweighted mean difference across calendar months was -0.17 hours/day compared with the earlier reference period; this is not a day-weighted annual average. Monthly changes varied: February had the largest increase, a difference of +0.22 hours/day, while May had the largest decrease, a difference of -0.91 hours/day. These extrema describe the largest reported monthly shifts, not a uniform change throughout the year.

Changes in snowfall

Mean daily snowfall, not monthly totals, averaged across calendar months had a difference of -0.04 mm/day in the more recent period. The aggregate difference summarizes monthly means and does not imply the same change in every month. The largest monthly decrease was in January, at a difference of -1.80 mm/day, while the largest increase was in March, at a difference of +1.08 mm/day. These monthly changes can differ in direction from the overall mean difference.