Climate Change Chart of Nashville, USA

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +0.86 °C compared with the earlier reference period; this is an unweighted mean of the monthly means, not a day-weighted annual average or a measure of daytime highs. The largest monthly increase was in December, with a difference of +2.14 °C. This identifies the strongest increase among the monthly means, rather than implying that every month changed by the same amount.

Changes in rainfall

Averaged across calendar months, mean daily rainfall has a difference of +1.20 mm/day in the more recent period. This unweighted average of monthly means describes daily rainfall amounts, not monthly rainfall totals, and does not mean that rainfall increased in every month. The largest monthly increase was in August, where mean daily rainfall had a difference of +3.32 mm/day. By contrast, the largest monthly decrease was in November, with a difference of -0.56 mm/day; these contrasting monthly changes show why the overall mean should not be read as applying uniformly through the year.

Changes in sunshine duration

Across calendar months, mean daily sunshine duration had an unweighted mean difference of -0.15 hours/day compared with the earlier reference period. This summary concerns average daily hours across the monthly means, not a day-weighted annual figure or the conditions on every day. The largest monthly increase occurred in January, with a difference of +0.48 hours/day, while the largest monthly decrease was in August, with a difference of -0.74 hours/day. These are monthly mean differences and do not describe day-to-day variability.

Changes in snowfall

Averaged across calendar months, mean daily snowfall had a difference of -0.21 mm/day in the more recent period. This is an unweighted average of monthly means for daily snowfall amounts, not a monthly total, and does not imply the same change in each month. The largest monthly decrease was in January, with a difference of -1.47 mm/day. The largest monthly increase was in February, with a difference of +0.08 mm/day, illustrating that the monthly snowfall differences did not all move in the same direction.