Climate Change Chart of Surrey, Canada

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +0.87 °C compared with the earlier reference period; this is an unweighted average of the monthly means, not a day-weighted annual average or a measure of daytime highs. The largest monthly increase was in January, at a difference of +3.04 °C. By contrast, September had the largest monthly decrease, a difference of -0.08 °C. These monthly extremes show that the changes varied by month rather than describing a uniform shift.

Changes in rainfall

Averaged across calendar months, mean daily rainfall had a difference of +0.03 mm/day; this small aggregate difference does not imply that rainfall shifted similarly in every month. The largest monthly increase was in September, with a difference of +1.66 mm/day, while February recorded the largest decrease, at a difference of -1.61 mm/day. These figures describe daily mean amounts, not monthly rainfall totals, and highlight contrasting monthly changes beneath the near-neutral average.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months had a difference of -0.61 hours/day compared with the earlier period; this unweighted average summarizes monthly means, rather than a day-weighted annual total. The largest monthly decrease occurred in September, at a difference of -1.28 hours/day. That monthly low point is more pronounced than the aggregate figure, so the mean should not be read as describing the change in each month.

Changes in snowfall

Mean daily snowfall, averaged across calendar months, had a difference of -0.08 mm/day. The largest monthly decrease was in January, with a difference of -3.56 mm/day, while the largest increase occurred in December, at a difference of +0.96 mm/day. The opposing monthly changes provide important context for the small aggregate difference; these are daily mean amounts, not monthly totals.