Climate Change Chart of Oslo, Norway

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +1.76 °C between the reference periods; this is an unweighted comparison of monthly means, not a day-weighted annual average or a measure of daytime highs. The strongest monthly rise was in January, with a difference of +6.22 °C. By contrast, August had the largest monthly decline, a difference of -0.25 °C. These month-specific differences show that the overall mean does not describe every month equally.

Changes in snowfall

Mean daily snowfall averaged across calendar months had a difference of +0.17 mm/day between the reference periods; this is an unweighted mean of monthly averages, not a day-weighted annual average or a monthly total. The month-to-month contrast was more pronounced: March had the largest increase, with a difference of +2.98 mm/day, whereas November had the largest decrease, with a difference of -4.23 mm/day. These figures concern mean daily snowfall and do not indicate that the same difference applied in every month or on every day.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months had a difference of -0.37 hours/day in the more recent period, an unweighted comparison of monthly means rather than a day-weighted annual average. The monthly pattern was not uniform: in May, mean daily sunshine had a difference of -1.35 hours/day, while April recorded an increase, with a difference of +0.33 hours/day. These differences describe average daily sunshine duration, not the conditions on every day, and the overall mean does not imply the same change in each month.

Changes in rainfall

Mean daily rainfall averaged across calendar months had a difference of +0.72 mm/day in the more recent period, an unweighted mean of monthly conditions rather than a day-weighted annual average. This is a daily-mean comparison, not a comparison of monthly rainfall totals. The largest monthly increase occurred in September, where mean daily rainfall had a difference of +1.39 mm/day. That standout month helps qualify the overall average: the mean difference summarizes the calendar-month averages and should not be read as the change in every month or on every day.