Climate Change Chart of Vantaa, Finland

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +1.79 °C in the more recent period. This is an unweighted average of the monthly means, rather than a day-weighted annual average, and describes the aggregate across months rather than every month's change. The largest monthly increase was in January, with a difference of +3.96 °C compared with the earlier reference period. This identifies the strongest monthly increase, not a change in daytime maximum temperatures.

Changes in snowfall

Averaged across calendar months, mean daily snowfall had a difference of +0.01 mm/day. This small aggregate difference does not mean monthly snowfall was unchanged, since it averages the monthly means and can conceal larger differences in particular months. The largest monthly increase was in January, with a difference of +1.98 mm/day; the largest decrease was in November, at -2.64 mm/day. These figures describe mean daily snowfall, not monthly totals, and show that month-specific differences can be more pronounced than the average across calendar months.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months had a difference of -0.10 hours/day compared with the earlier reference period. This unweighted average summarizes the monthly means and does not imply the same difference in every month. The largest monthly increase occurred in June, with a difference of +0.95 hours/day; the largest decrease was in October, at -0.94 hours/day. These monthly differences show contrasting changes in mean daily sunshine, rather than a uniform shift across the calendar.

Changes in rainfall

Averaged across calendar months, mean daily rainfall had a difference of +0.27 mm/day in the more recent period. This unweighted average describes the monthly means collectively, not each month's rainfall or a monthly total. Among the supplied monthly differences, the largest increase was in October, at +0.73 mm/day. By contrast, September had the largest decrease, a difference of -0.27 mm/day; these are changes in mean daily rainfall, not monthly accumulations.