Climate Change Chart of Tromsø, Norway

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +1.94 °C compared with the earlier reference period; this is an unweighted comparison of monthly means, not a day-weighted annual average or a measure of daytime maximum temperatures. The largest monthly increase was in March, at +3.72 °C, so that month stands out within the supplied temperature differences without implying the same change in every month.

Changes in snowfall

Averaged across calendar months, mean daily snowfall has a difference of +2.12 mm/day compared with the earlier reference period. This unweighted average concerns daily amounts, not monthly snowfall totals, and does not establish that the difference was the same in every month. The largest monthly increase was in March, at +8.93 mm/day, whereas the largest decrease occurred in October, with a difference of -1.34 mm/day. These figures describe recorded snowfall differences and do not imply that snowfall was absent in any period.

Changes in rainfall

Averaged across calendar months, mean daily rainfall has a difference of +0.28 mm/day compared with the earlier reference period. This unweighted average of monthly means describes daily amounts rather than monthly totals, and does not mean every month became wetter. The largest monthly increase occurred in June, with a difference of +1.35 mm/day, while the largest decrease was in January, at -0.49 mm/day. These opposing monthly changes show why the average should be read alongside the month-specific differences.

Changes in sunshine duration

Mean daily sunshine duration, averaged across calendar months, shows a difference of -0.14 hours/day compared with the earlier reference period. This is an unweighted comparison of monthly means, not a day-weighted annual measure. The largest monthly decrease occurred in June, with a difference of -0.80 hours/day; by contrast, the largest increase was in August, at +0.37 hours/day. The overall mean and these monthly extremes describe different aspects of the comparison, rather than a uniform change through the year.