Climate Change Chart of Boise, USA

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +1.54 °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 maximum temperatures. The largest monthly increase was in January, with a difference of +4.13 °C, while October had the largest monthly decrease, a difference of -0.21 °C.

Changes in snowfall

Averaged across calendar months, mean daily snowfall had a difference of -0.25 mm/day in the more recent period. This unweighted comparison summarizes monthly means and does not establish that every month changed in the same way. The largest monthly decrease was in February, with a difference of -1.62 mm/day; by contrast, April had the largest increase, a difference of +0.08 mm/day. These figures describe mean daily snowfall, not monthly totals.

Changes in rainfall

Averaged across calendar months, mean daily rainfall had a difference of +0.05 mm/day in the more recent period; this unweighted mean of monthly means describes an overall comparison, not a change shared by every month. The largest monthly increases occurred in January / May, with a difference of +0.32 mm/day, while November recorded the largest decrease, a difference of -0.43 mm/day. These are differences in mean daily amounts, not monthly rainfall totals.

Changes in sunshine duration

Averaged across calendar months, mean daily sunshine duration shows a difference of -0.30 hours/day compared with the earlier period; this unweighted summary of monthly means does not imply the same change in every month. The largest monthly increase was in November, with a difference of +0.18 hours/day. The largest monthly decreases were in April / December, each associated with a difference of -0.53 hours/day.