Climate Change Chart of Bismarck, USA

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +0.84 °C compared with the earlier reference period; this unweighted mean summarizes the monthly averages, rather than a day-weighted annual average or daytime maximum temperatures. The largest monthly increase was in June, with a difference of +2.75 °C. By contrast, October had the largest monthly decrease, a difference of -1.12 °C. These are specific monthly contrasts and do not imply that every month changed in the same direction.

Changes in snowfall

Mean daily snowfall averaged across calendar months had a difference of +0.17 mm/day. This is an unweighted summary of monthly means, not a monthly snowfall total, and it does not imply that snowfall changed by the same amount in each month. The largest monthly increase was in December, with a difference of +2.85 mm/day; the largest monthly decrease was in May, with a difference of -1.87 mm/day. These contrasting monthly results provide context for the overall mean, while describing averages rather than snowfall on any particular day.

Changes in rainfall

Mean daily rainfall, averaged across calendar months, had a difference of -0.12 mm/day. This is an unweighted summary of monthly means, not a change in monthly totals, and it does not mean that daily rainfall was lower in every month. The largest monthly decrease occurred in July, with a difference of -0.77 mm/day; the largest monthly increase was in October, with a difference of +0.28 mm/day. Together, these month-specific results show why the overall mean should not be read as describing each month’s daily rainfall.

Changes in sunshine duration

For mean daily sunshine duration, the difference averaged across calendar months was +0.11 hours/day, based on unweighted monthly means rather than a day-weighted annual average. This overall result does not indicate the same change in every month. The largest increase was in June, at a difference of +2.07 hours/day, while the largest decrease was in October, at a difference of -0.76 hours/day. These monthly differences describe mean daily hours, not the sunshine duration on every day.