Climate Chart of Hiroshima, Japan

Monthly data: Temperature °C, Rain (mm), Sunshine (h) · 2013–2023

For Hiroshima, Japan, the climate data cover 2013–2023. Across the calendar-month means, temperature averages 15.8 °C, while mean daily rainfall averages 4.47 mm/day. The pattern spans a coolest monthly mean of 5.3 °C in January and a warmest of 27.3 °C in August. These figures give an overview rather than a forecast: monthly temperature means are not daytime highs, and rainfall figures describe daily averages, not monthly totals.

Climate overview

Temperature

Monthly mean temperatures reach their highest at 27.3 °C in August, while the lowest monthly mean is 5.3 °C in January. This range helps set expectations for the annual temperature pattern, but neither figure describes the daytime maximum or the conditions on any particular day. The unweighted mean across monthly means is 15.8 °C. It summarizes the calendar-month averages without accounting for the differing number of days in each month, so it should not be read as a day-weighted annual average.

Rain

Mean daily rainfall is highest at 8.64 mm/day in July and lowest at 1.81 mm/day in January. These are daily averages for the respective months, not monthly rainfall totals; they also do not indicate how often rain falls or guarantee conditions on a particular day. The unweighted mean of the monthly daily-rainfall averages is 4.47 mm/day. It offers a broad reference for the year, while the month-specific figures are more useful for understanding how the averages differ across the calendar.

Sunshine

Mean daily sunshine reaches 9.83 hours/day in August, with its lowest monthly mean at 6.65 hours/day in December. These averages can help with broad outdoor-planning expectations, but sunshine duration is not the same as daylight length and does not promise clear skies on an individual day. Across the calendar-month means, mean daily sunshine is 8.27 hours/day. This is an unweighted summary of monthly averages, rather than a day-weighted annual figure.

Snow

The highest monthly mean daily snowfall is 0.70 mm/day in February. The unweighted mean across monthly snowfall averages is 0.12 mm/day. These daily amounts describe averages, not the number of snowy days, snow depth, snow cover, or skiing conditions.

Best Travel Time Guide for Hiroshima, Japan: Ideal Seasons and Weather Insights

For visitors prioritising cooler monthly-average temperatures, January is the relevant option in the supplied data, with a mean of 5.3 °C; this describes a monthly average, not a guarantee of cool weather throughout a visit. Those seeking the lowest average daily rainfall could consider January, at 1.81 mm/day, while allowing for rainy days because a lower mean does not establish rain frequency or ensure dry conditions. Rain preparation is particularly relevant when travelling in July, where mean daily rainfall is 8.64 mm/day. This average does not specify the timing or duration of rainfall, so it cannot predict the weather on a chosen day.

For outdoor sightseeing planned around average sunshine duration, August has the highest monthly mean at 9.83 hours/day, while December has the lowest at 6.65 hours/day. These are separate considerations, not a combined best-time ranking; sunshine hours are not daylight length and do not guarantee clear skies. In February, the highest mean daily snowfall is 0.70 mm/day, but that amount cannot establish how many days will see snow or whether snow will accumulate.

Climate Data Overview for Hiroshima, Japan

Explore the comprehensive climate data for Hiroshima, Japan. This detailed table provides valuable insights into temperature variations, precipitation levels, and seasonal changes, helping you understand the unique weather patterns of this region.

Month	Average: Temperature °C	Rain (mm) / day	Snow (mm) / day	Sunshine (h) / day
Jan	5.3	1.81	0.61	7.15
Feb	5.8	2.13	0.70	7.55
Mar	9.6	3.59	0.00	8.51
Apr	13.6	4.96	0.00	8.83
May	18.3	4.10	0.00	9.18
Jun	21.8	7.17	0.00	8.29
Jul	25.9	8.64	0.00	9.24
Aug	27.3	6.66	0.00	9.83
Sep	23.6	6.60	0.00	8.26
Oct	18.1	3.92	0.00	8.03
Nov	12.7	2.01	0.00	7.70
Dec	7.3	2.10	0.11	6.65
Average	15.8	4.47	0.12	8.27