Climate Change Chart of Sendai, Japan

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +1.09 °C in the more recent period; this is an unweighted comparison of monthly means, not a day-weighted annual average or a measure of daytime highs. The monthly pattern was not uniform: June had the largest increase, a difference of +2.55 °C, while October had the largest decrease, a difference of -0.37 °C. These month-specific comparisons describe the period averages for those months, rather than a continuous change between the reference periods.

Changes in sunshine duration

Mean daily sunshine duration averaged across calendar months had a difference of -0.58 hours/day in the more recent period, based on an unweighted comparison of monthly means. The monthly differences varied: February had the largest decrease, a difference of -1.06 hours/day, whereas June had the largest increase, a difference of +0.21 hours/day. These period-average comparisons concern daily sunshine hours and do not describe every day or establish a continuous trend between the reference periods.

Changes in snowfall

Mean daily snowfall averaged across calendar months had a difference of +0.55 mm/day between the periods; this is an unweighted comparison of monthly averages, not a day-weighted annual snowfall total. The largest monthly increase occurred in January, with a difference of +3.53 mm/day, while the largest monthly decrease was in March, at a difference of -0.71 mm/day. These differences describe recorded daily-average snowfall for the indicated months and do not mean that snowfall changed uniformly across the calendar or from day to day.

Changes in rainfall

Mean daily rainfall, rather than monthly totals, averaged across calendar months shows a difference of +0.79 mm/day between the reference periods; this is an unweighted mean of monthly averages, not a day-weighted annual figure. The largest monthly increase was in August, with a difference of +2.17 mm/day, while September recorded the largest decrease, a difference of -0.20 mm/day. Those contrasts identify changes in the respective monthly daily means and do not imply that rainfall changed in the same direction in every month or on every day.