Climate Change Chart of Trondheim, Norway

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +2.11 °C in the more recent period; this unweighted mean of monthly averages is not a day-weighted annual average or a measure of daytime highs. The largest monthly increase was in January, with a difference of +6.80 °C. By contrast, July had the largest monthly decrease, a difference of -0.22 °C; these month-specific changes show that the overall mean does not describe every calendar month.

Changes in snowfall

Mean daily snowfall averaged across calendar months had a difference of -1.09 mm/day in the more recent period. This unweighted summary describes the difference between monthly means, not monthly snowfall totals or conditions on every day. The largest monthly decrease was in February, with a difference of -4.54 mm/day in mean daily snowfall. The largest increase occurred in May, a difference of +0.08 mm/day, so the overall mean difference does not represent every month's change.

Changes in rainfall

Mean daily rainfall, rather than monthly totals, averaged across calendar months has a difference of +0.67 mm/day compared with the earlier reference period. This is an unweighted average of monthly means, so it summarizes the overall monthly pattern without implying that rainfall rose in every month or on every day. The largest monthly increase occurred in December, a difference of +1.26 mm/day in mean daily rainfall. In April, the largest monthly decrease was a difference of -0.08 mm/day, highlighting a contrasting month-specific change.

Changes in sunshine duration

For mean daily sunshine duration, the unweighted average across calendar-month means had a difference of -0.07 hours/day between the reference periods. This summary is not day-weighted and does not mean the same change occurred in each month. The largest monthly increase was in June, where mean daily sunshine had a difference of +0.53 hours/day. The largest decrease came in May, with a difference of -0.66 hours/day; these contrasting results underscore the limits of the small overall mean difference as a description of individual months.