Climate Change Chart of Indianapolis, USA

Overview of climate changes

Temperature changes

Monthly mean temperature was higher by a mean difference of +1.24 °C averaged across calendar months; this is an unweighted summary of monthly means, not a day-weighted annual average or a measure of daytime maximum temperatures. The largest monthly increase was in December, with a difference of +2.60 °C. This identifies the strongest increase among the reported monthly changes, rather than showing that every month warmed by the same amount.

Changes in rainfall

Mean daily rainfall increased by a mean difference of +0.38 mm/day averaged across calendar months. This unweighted comparison summarizes monthly means, and the figures describe daily mean amounts rather than monthly rainfall totals. The largest monthly increase occurred in July, at a difference of +1.56 mm/day, while the largest decrease was in November, at a difference of -0.60 mm/day. These contrasting monthly changes show why the overall mean should not be read as a change shared by every month.

Changes in sunshine duration

Mean daily sunshine duration had a mean difference of -0.23 hours/day averaged across calendar months, indicating a lower unweighted average of the monthly means in the more recent period; this is not a day-weighted annual average. The largest decrease was in July, with a difference of -0.93 hours/day. In contrast, June recorded the largest increase, at a difference of +0.42 hours/day, so the monthly changes did not all follow the overall mean.

Changes in snowfall

Mean daily snowfall increased by a mean difference of +0.19 mm/day averaged across calendar months. This is an unweighted comparison of monthly means, not a day-weighted annual average, and it describes daily mean amounts rather than monthly totals. The largest monthly increase was in February, with a difference of +1.75 mm/day; the largest decrease was in December, with a difference of -1.01 mm/day. These opposing monthly differences qualify the small overall mean change without implying that snowfall changed uniformly across months.