Climate Change Chart of Juneau, USA

Overview of climate changes

Changes in snowfall

Mean daily snowfall averaged across calendar months had a difference of +6.52 mm/day compared with the earlier reference period. This is an unweighted average of monthly means, not a day-weighted annual average or a monthly total. The largest monthly increase was in February, with a difference of +21.03 mm/day; the largest decrease was in May, a difference of -0.34 mm/day. These period-average comparisons show that monthly differences varied and do not describe every day's snowfall.

Changes in rainfall

Mean daily rainfall averaged across calendar months had a difference of +1.05 mm/day in the more recent period. This is an unweighted average of monthly means, not a day-weighted annual average or a monthly rainfall total. The largest monthly increase was in August, with a difference of +4.31 mm/day; by contrast, March recorded the largest decrease, a difference of -0.65 mm/day. These monthly comparisons describe averages across the reference periods and do not mean that rainfall changed by the same amount on every day.

Temperature changes

Averaged across calendar months, the difference in monthly mean temperature was +0.64 °C compared with the earlier reference period; this is an unweighted mean of the monthly means, not a day-weighted annual average or a measure of daytime highs. The monthly pattern was not uniform: June had the largest increase, a difference of +2.81 °C, while March had the largest decrease, a difference of -1.50 °C. These are differences between period averages for those months, not evidence of a continuous change between the periods.

Changes in sunshine duration

Across calendar months, mean daily sunshine duration had a difference of +0.02 hours/day in the more recent period; this is an unweighted mean of monthly means, not a day-weighted annual figure. The largest monthly increase occurred in July, with a difference of +0.83 hours/day, while June had the largest decrease, a difference of -0.63 hours/day. The small overall mean difference does not imply the same change in each month.