Climate Change Chart of Arapahoe Basin, USA

Overview of climate changes

Changes in snowfall

Mean daily snowfall averaged across calendar months had a difference of +2.03 mm/day; this unweighted mean of monthly means is not a monthly total or a day-weighted annual average. The largest monthly increase was in May, with a difference of +6.58 mm/day, while the largest decrease was in April, at -0.38 mm/day. These daily-mean comparisons point to contrasting month-specific differences, rather than a uniform change through the year.

Temperature changes

Averaged across calendar months, the difference in monthly mean temperature was +3.11 °C; this is an unweighted mean of monthly means, not a day-weighted annual average or a measure of daytime highs. The largest monthly increase was in November, with a difference of +5.05 °C compared with the earlier reference period. That monthly contrast identifies the strongest increase, not a uniform change across all months.

Changes in rainfall

Mean daily rainfall, rather than monthly totals, had an averaged-across-calendar-months difference of -0.20 mm/day. This unweighted summary does not imply that every month was drier. The largest monthly decrease was in August, with a difference of -0.74 mm/day; by contrast, the largest increase was shared by February / March / November, at +0.01 mm/day. These month-specific differences show that the direction and size of the comparison varied within the year.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months had a difference of -0.28 hours/day, expressed as an unweighted mean of the monthly means rather than a day-weighted annual average. The largest monthly decrease occurred in May, at -0.64 hours/day. This describes a month-specific contrast and does not establish that sunshine declined in every calendar month.