Climate averages 1991–2020
Hiroshima weather
in August.
A hot, wet month: the warmest and the 9th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
August is a hot month in Hiroshima: daytime highs average 30.4°C and nights cool to about 23.8°C. By daytime temperature it is the warmest month of the year.
Expect about 157 mm of rain on roughly 14 days, which makes August a wet month (the 9th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 13 h 26 min on an average August day.
The nearest other city in this atlas is Hatsukaichi (12 km away). In August its highs average 30.9°C, about as warm as Hiroshima, with 169 mm of rain.
Among the 303 cities listed in Japan, Hiroshima ranks joint 62nd of 303 for the warmest August highs and joint 178th of 303 for the driest August (rainfall, lowest first). The mean August high of those 303 cities is 29.2°C; Hiroshima is 1.3°C warmer than that mean.
From August to September, average highs fall by 3.6°C to 26.9°C, and monthly rainfall rises from 157 mm to 188 mm.
The annual picture
August in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Hiroshima climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 8.0°C1.1°C | 1.1°C | 55 | 9.5 | 10.110 h |
| February | 9.3°C1.3°C | 1.3°C | 68 | 9.9 | 10.911 h |
| March | 13.1°C3.9°C | 3.9°C | 110 | 11.7 | 11.912 h |
| April | 18.3°C8.7°C | 8.7°C | 124 | 10.3 | 13.013 h |
| May | 22.8°C13.8°C | 13.8°C | 143 | 10.3 | 13.914 h |
| June | 25.8°C18.5°C | 18.5°C | 215 | 14.3 | 14.414 h |
| July | 29.1°C22.8°C | 22.8°C | 251 | 16.1 | 14.214 h |
| August, selected | 30.4°C23.8°C | 23.8°C | 157 | 14.0 | 13.413 h |
| September | 26.9°C19.9°C | 19.9°C | 188 | 12.6 | 12.412 h |
| October | 21.5°C13.7°C | 13.7°C | 109 | 8.2 | 11.311 h |
| November | 15.9°C8.2°C | 8.2°C | 71 | 8.1 | 10.410 h |
| December | 10.3°C3.4°C | 3.4°C | 64 | 9.6 | 9.910 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
August in nearby cities
- Hatsukaichi in AugustJapan · 12 kmHigh 30.9°C · Low 24.3°C · 169 mm rain
- Kure in AugustJapan · 22 kmHigh 28.4°C · Low 24.2°C · 120 mm rain
- Higashihiroshima in AugustJapan · 26 kmHigh 29.6°C · Low 23.1°C · 132 mm rain
- Iwakuni in AugustJapan · 34 kmHigh 29.8°C · Low 24.4°C · 169 mm rain
- Mihara in AugustJapan · 58 kmHigh 30.9°C · Low 24.3°C · 125 mm rain
- Imabari in AugustJapan · 62 kmHigh 29.7°C · Low 25.0°C · 142 mm rain
- Shūnan in AugustJapan · 67 kmHigh 28.3°C · Low 22.6°C · 147 mm rain
- Matsuyama in AugustJapan · 69 kmHigh 30.7°C · Low 24.9°C · 156 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Hiroshima) is explained once on the Hiroshima year overview and on the Sources, method and limits page.