Climate Change Chart of Tokyo, Japan

Overview of climate changes

Temperature changes

Averaged across calendar months, monthly mean temperature shows a difference of +1.20 °C compared with the earlier reference period; this unweighted summary describes the set of monthly means, not daytime highs or a day-weighted annual average. The largest monthly increase in this measure occurred in March, with a difference of +2.32 °C. This marks the strongest month-specific increase in the supplied temperature differences, rather than a change applying uniformly to every month.

Changes in rainfall

Mean daily rainfall averaged across calendar months had a difference of +1.30 mm/day in the more recent period. This unweighted comparison summarizes the monthly means; it is not a monthly rainfall total or a day-weighted annual average. The largest monthly increase in mean daily rainfall was in September, with a difference of +2.56 mm/day. By contrast, November had the largest monthly decrease, a difference of -0.04 mm/day; these month-specific differences need not describe other months.

Changes in sunshine duration

Averaged across calendar months, mean daily sunshine duration had a difference of -0.40 hours/day compared with the earlier period. This is an unweighted summary of the calendar-month means, not a day-weighted annual measure. The largest monthly decrease was in February, with a difference of -0.87 hours/day. In June, sunshine instead recorded the largest monthly increase, a difference of +0.33 hours/day, showing that the aggregate difference does not apply equally across the calendar months.

Changes in snowfall

Mean daily snowfall averaged across calendar months had a difference of +0.25 mm/day in the more recent period. This unweighted summary concerns monthly means rather than monthly snowfall totals, and does not imply that the same difference occurred in every month. The largest monthly increase in mean daily snowfall occurred in February, with a difference of +1.81 mm/day. The largest monthly decrease was in March, a difference of -0.22 mm/day; these month-specific shifts show why the overall mean difference does not describe each month individually.