Climate Change Chart of Columbia, USA

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +0.74 °C compared with the earlier reference period; this is an unweighted mean of monthly means, not a day-weighted annual average or a measure of daytime highs. The largest monthly mean temperature increase was in December, with a difference of +2.22 °C. By contrast, November had the largest decrease, at -0.21 °C; these identify the strongest monthly changes rather than a uniform change in every month.

Changes in rainfall

Averaged across calendar months, mean daily rainfall had a difference of +0.81 mm/day. This unweighted comparison of monthly means describes daily amounts, not monthly rainfall totals, and does not imply that rainfall rose in every month. The largest monthly increase in mean daily rainfall occurred in July, with a difference of +1.91 mm/day. In January, the largest decrease was -0.30 mm/day, showing that the monthly differences were not all in the same direction.

Changes in snowfall

Averaged across calendar months, mean daily snowfall had a difference of +0.24 mm/day. This unweighted mean of monthly daily amounts is not a monthly total, and it summarizes the calendar months rather than indicating the same difference in each one. The largest increase in mean daily snowfall occurred in March, with a difference of +1.55 mm/day. The largest decrease was in December, at -0.88 mm/day; these contrasting monthly differences describe recorded snowfall amounts, not snowfall totals for those months.

Changes in sunshine duration

Mean daily sunshine duration, averaged across calendar months, had a difference of -0.23 hours/day compared with the earlier period. This is an unweighted mean of monthly daily-hour averages, not a day-weighted annual figure or a description of every month. The largest monthly decrease was in February, at -0.74 hours/day; the largest increase came in July, with a difference of +0.47 hours/day. These are the monthly extremes, while the overall mean difference summarizes the months together.