Climate Change Chart of Guimarães, Portugal

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +0.88 °C compared with the earlier reference period; this is an unweighted average of monthly means, not a day-weighted annual average or a measure of daytime maximum temperatures. The monthly differences were not uniform: the largest increase was in December, at a difference of +2.03 °C, while June had the largest decrease, a difference of -0.38 °C. These are comparisons of period averages for those months, not evidence of a continuous change between the periods.

Changes in rainfall

Mean daily rainfall, rather than monthly rainfall totals, had an average difference across calendar months of +0.68 mm/day. This is an unweighted summary of the monthly means, so it does not imply that every month was wetter. The largest monthly increase occurred in October, with a difference of +3.24 mm/day; in contrast, May recorded the largest decrease, a difference of -1.08 mm/day. These monthly contrasts describe differences between the reference-period averages, not a continuous pattern over time.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months had a difference of -0.60 hours/day compared with the earlier reference period. This unweighted mean of monthly averages does not mean that every month had less sunshine. The largest monthly decrease was in June, where the difference was -1.13 hours/day. The figures compare period averages; they do not establish a continuous change between the reference periods.

Changes in snowfall

For mean daily snowfall, the average difference across calendar months was -0.01 mm/day. This is an unweighted average of monthly means, not a monthly total, and it does not describe every month individually. The largest monthly decrease was in February, at a difference of -0.18 mm/day, while March had the largest increase, with a difference of +0.02 mm/day. These recorded differences compare period averages and should not be read as evidence of a continuous change.