Climate Change Chart of Powder Mountain, USA

Overview of climate changes

Changes in snowfall

Mean daily snowfall showed an unweighted average difference across calendar months of +0.46 mm/day compared with the earlier reference period; this is not a comparison of monthly snowfall totals or a day-weighted annual average. The largest monthly increase was in April, with a difference of +3.20 mm/day, while May had the largest decrease, at -0.96 mm/day. The contrasting changes indicate that snowfall differences varied across the months, so the average increase should not be taken to mean an increase in every month.

Temperature changes

Averaged across calendar months, monthly mean temperature showed a difference of +1.35 °C compared with the earlier reference period; this unweighted comparison of monthly means is not a day-weighted annual average or a description of daytime highs. The largest monthly increase was in January, with a difference of +4.07 °C. In contrast, October had the largest monthly decrease, a difference of -0.94 °C. These extrema show that the period-to-period temperature differences varied by month, rather than moving uniformly across the calendar.

Changes in rainfall

Mean daily rainfall, rather than monthly rainfall totals, was lower on average across calendar months: the unweighted mean difference was -0.18 mm/day compared with the earlier reference period. The clearest monthly decrease was in June, where the difference was -1.68 mm/day. The largest monthly increase occurred in September, at a difference of +0.22 mm/day. The overall mean and these contrasting monthly changes describe different aspects of the comparison; the mean does not imply that rainfall decreased in every month.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months had a difference of -0.26 hours/day, an unweighted comparison of monthly means rather than a day-weighted annual average. Monthly changes were mixed: June recorded the largest increase, with a difference of +1.38 hours/day, while the largest decrease was in May, at -0.89 hours/day. These monthly contrasts help qualify the overall mean, which should not be read as a decrease in every month.