Climate Change Chart of Rio de Janeiro, Brazil

Overview of climate changes

Changes in rainfall

Averaged across calendar months, mean daily rainfall had a difference of -0.55 mm/day compared with the earlier reference period. This unweighted comparison of monthly means is not a day-weighted annual average, and it describes mean daily amounts rather than monthly totals. The largest monthly decrease was in December, with a difference of -3.45 mm/day. By contrast, July had the largest monthly increase, at +0.19 mm/day. These contrasting monthly changes show why the overall mean difference should not be read as a uniform shift in every month.

Temperature changes

The mean difference across calendar months was an increase of +1.08 °C in monthly mean temperature. This is a comparison of monthly averages, not daytime maximum temperatures, and does not mean every month had the same change. The largest monthly increase was in January, at +1.91 °C; that identifies the strongest increase, not the pattern for all months.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months had a difference of +0.08 hours/day between the reference periods. This is an unweighted mean of monthly averages, rather than a day-weighted annual figure. The largest monthly increase occurred in December, with a difference of +1.08 hours/day, while the largest monthly decrease was in November, at -0.30 hours/day. The small overall mean difference therefore summarizes varied monthly changes; it does not imply that sunshine duration increased in every month.