Climate Change Chart of Richmond, USA

Overview of climate changes

Temperature changes

Monthly mean temperature averaged across calendar months shows a difference of +0.36 °C compared with the earlier reference period; this is an unweighted mean of monthly averages, not a day-weighted annual average or a measure of daytime maximum temperatures. The largest monthly increase was in January, with a difference of +2.25 °C, while the largest monthly decrease was in July, with a difference of -1.80 °C. These are the most pronounced monthly changes in opposite directions, rather than evidence that every month changed alike.

Changes in rainfall

Mean daily rainfall, averaged across calendar months, had a difference of -0.09 mm/day in the more recent period. This unweighted summary describes monthly means, not monthly rainfall totals or a day-weighted annual average. The largest monthly increase was in December, with a difference of +0.44 mm/day; the largest monthly decrease was in April, with a difference of -0.67 mm/day. These daily-mean changes highlight contrasting month-specific shifts and do not imply the same difference in every month.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months had a difference of -0.02 hours/day compared with the earlier reference period. This is an unweighted summary of monthly means, rather than a day-weighted annual average. The largest monthly increase occurred in February, with a difference of +0.67 hours/day, while the largest decrease was in August, with a difference of -0.36 hours/day. The month-specific contrasts show why the overall mean difference should not be read as a uniform change throughout the calendar.

Changes in snowfall

Mean daily snowfall averaged across calendar months was unchanged at the displayed precision, with a difference of 0.00 mm/day. This rounded aggregate does not establish that snowfall was absent or that no smaller differences occurred. The largest monthly increase was in February, with a difference of +0.02 mm/day. This is a change in mean daily snowfall, not a monthly snowfall total, and does not mean that every month increased.