Climate Change Chart of Hiroshima, Japan

Overview of climate changes

Changes in rainfall

Mean daily rainfall was higher by +1.61 mm/day when the monthly means are averaged across calendar months, an unweighted summary rather than a day-weighted annual figure. The largest monthly increase was in August, at +4.35 mm/day; by contrast, November recorded the largest decrease, -0.04 mm/day. These are differences in mean daily amounts, not monthly rainfall totals, and the overall mean should not be read as a change applying uniformly to each month.

Temperature changes

Averaged across calendar months, the difference in monthly mean temperature was -0.01 °C; this is an unweighted comparison of monthly means, not a day-weighted annual average or a measure of daytime highs. The monthly extremes went in opposite directions: August had the largest increase, +0.93 °C, while December had the largest decrease, -1.00 °C. These selected months show that the near-neutral mean difference does not describe every month’s comparison.

Changes in sunshine duration

Mean daily sunshine duration had an unweighted difference of -0.77 hours/day averaged across calendar months, rather than a day-weighted annual comparison. The largest monthly decrease was in August, with a difference of -1.23 hours/day. The mean summarizes monthly averages; it does not imply the same difference in every month or describe daily conditions across the periods.

Changes in snowfall

For mean daily snowfall, the unweighted difference averaged across calendar months was -0.02 mm/day. The monthly comparison varied: February had the largest decrease, -0.21 mm/day, while January had the largest increase, +0.07 mm/day. These are differences in mean daily amounts, not monthly snowfall totals; the small overall mean difference does not mean snowfall was absent or unchanged in every month.