Climate Change Chart of Pori, Finland

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +1.80 °C compared with the earlier reference period; this is an unweighted average of the monthly means, not a day-weighted annual average or a measure of daytime maximum temperatures. The largest monthly increase was in February, with a difference of +3.73 °C. That identifies the strongest increase among the supplied monthly differences, rather than describing every month or a continuous change between the reference periods.

Changes in snowfall

Averaged across calendar months, mean daily snowfall had a difference of -0.24 mm/day compared with the earlier reference period. This is an unweighted average of monthly means, not a day-weighted annual amount, and it describes a difference at the displayed precision rather than snowfall in every month. The largest monthly increase was in January, with a difference of +0.54 mm/day; the largest decrease was in November, at -1.72 mm/day. These opposite monthly changes do not establish a uniform pattern across the calendar.

Changes in rainfall

Averaged across calendar months, mean daily rainfall had a difference of +0.30 mm/day compared with the earlier reference period. This unweighted average of monthly means describes the aggregate difference, not a day-weighted annual total; the amounts are daily means, not monthly totals. Monthly differences varied: in July, the largest increase was +1.03 mm/day, while September had the largest decrease, a difference of -0.43 mm/day. These two months mark the supplied extremes in opposite directions and do not imply that rainfall changed the same way in other months.

Changes in sunshine duration

Mean daily sunshine duration had an unweighted difference across calendar-month means of -0.06 hours/day compared with the earlier reference period. This summarizes the monthly means rather than a day-weighted annual average. The largest monthly increase occurred in June, at +0.61 hours/day; the largest decrease was in August, at -0.49 hours/day. These contrasting monthly differences show why the overall mean should not be read as a description of every month or as evidence of a continuous change between periods.