Climate Change Chart of Helsinki, Finland

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference/change of +1.95 °C compared with the earlier reference period; this unweighted mean describes the aggregate of the monthly means, not a day-weighted annual average or the temperature in every month. The largest monthly increase was in January, with a difference/change of +5.02 °C. In contrast, July had the largest monthly decrease, a difference/change of -0.70 °C. These are monthly mean temperatures, not daytime maxima.

Changes in snowfall

For mean daily snowfall, the unweighted mean of monthly averages across calendar months had a difference/change of -0.37 mm/day compared with the earlier reference period. This aggregate does not describe every month, and the figures are daily means rather than monthly totals. Monthly changes were not uniform: January had the largest increase, a difference/change of +1.11 mm/day, while November had the largest decrease, a difference/change of -2.80 mm/day.

Changes in rainfall

Averaged across calendar months, mean daily rainfall had a difference/change of +0.29 mm/day compared with the earlier reference period. This unweighted average of monthly means is not a day-weighted annual average, and it does not mean rainfall increased in every month. The largest monthly increase was in October, at a difference/change of +0.90 mm/day, while July recorded the largest monthly decrease, a difference/change of -0.38 mm/day. These figures describe mean daily amounts rather than monthly rainfall totals.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months shows a difference/change of -0.03 hours/day compared with the earlier reference period. This unweighted mean across monthly averages is not day-weighted, and the small overall difference does not imply that each month changed by the same amount or in the same direction. The largest monthly increase occurred in June, with a difference/change of +0.97 hours/day; the largest monthly decrease was in October, with a difference/change of -0.82 hours/day. The monthly figures are mean daily hours of sunshine.