Climate Change Chart of Niagara Falls, Canada

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +1.11 °C compared with the earlier reference period; this is an unweighted average of monthly means, not a day-weighted annual figure or a measure of daytime highs. The largest monthly increase was in December, with a difference of +2.11 °C. By contrast, November had the largest monthly decrease, a difference of -0.40 °C.

Changes in rainfall

The unweighted mean difference in mean daily rainfall, averaged across calendar months, was +0.03 mm/day. This summarizes the monthly averages and should not be read as a difference in monthly rainfall totals or as a change applying to every month. Monthly differences were uneven: October recorded the largest increase, a difference of +0.67 mm/day, while May recorded the largest decrease, a difference of -1.10 mm/day. These figures describe mean daily amounts, not monthly totals.

Changes in sunshine duration

Averaged across calendar months, mean daily sunshine duration had a difference of -0.32 hours/day; this is an unweighted summary of the monthly means rather than a day-weighted annual measure. The largest monthly increase was in May, with a difference of +0.95 hours/day, whereas October had the largest monthly decrease, a difference of -1.23 hours/day. The contrast shows why the overall mean difference does not describe each month's change.

Changes in snowfall

The unweighted mean difference in mean daily snowfall, averaged across calendar months, was -0.29 mm/day. It summarizes monthly mean amounts, not monthly snowfall totals, and does not indicate that snowfall was absent in either reference period. The largest monthly increase in mean daily snowfall was in November, with a difference of +0.40 mm/day. The largest decrease occurred in March, a difference of -2.02 mm/day; these monthly contrasts need not match the overall mean difference.