Climate Change Chart of Longyearbyen, Norway

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +4.18 °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 highs. The largest monthly increase was in February, with a difference of +6.55 °C. This identifies the strongest reported monthly increase, rather than implying that temperatures rose by the same amount in every month.

Changes in sunshine duration

Averaged across calendar months, mean daily sunshine duration shows a difference of -0.98 hours/day compared with the earlier period. This is an unweighted mean of monthly averages, so it summarizes the calendar months collectively rather than describing each month's change. Monthly differences varied: the largest decrease was in June, at -4.46 hours/day, while the largest increase was in February, at +0.31 hours/day. These extrema show that the overall mean does not represent every month's direction or magnitude.

Changes in rainfall

Mean daily rainfall, rather than monthly rainfall totals, averaged across calendar months shows a difference of +0.15 mm/day. This unweighted mean describes the aggregate comparison between the reference periods; it does not mean every month's daily average increased by that amount. The largest monthly increase in mean daily rainfall occurred in August, with a difference of +0.48 mm/day. This points to a particularly clear monthly contrast, not a change applying uniformly throughout the year.

Changes in snowfall

Averaged across calendar months, mean daily snowfall has an unchanged difference of 0.00 mm/day at the displayed precision. This rounded aggregate does not establish that all monthly values were identical between the reference periods. The monthly pattern nevertheless includes a difference of +2.78 mm/day in February and a difference of -3.70 mm/day in October. These are the largest increase and decrease respectively; daily amounts are not monthly snowfall totals.