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Iwakuni Weather by Month
Average temperatures, rainfall and humidity for Iwakuni, Japan, month by month, built from OpenWeather’s historical records. Use it to see what a typical Iwakuni month looks like before you travel — then check the live Iwakuni forecast for the days ahead.
Warmest month
August
32°C average high
Coolest month
January
2°C average low
Wettest month
June
164 mm of rain
Driest month
January
42 mm of rain
Average temperature and rainfall in Iwakuni by month
Averages of the daily highs and lows recorded in each month, with total rainfall, mean humidity and mean wind speed.
| Month | Avg high | Avg low | Record low / high | Rainfall | Humidity | Wind |
|---|---|---|---|---|---|---|
| January | 10°C | 2°C | -7°C / 36°C | 42 mm | 66% | 12 km/h |
| February | 10°C | 3°C | -8°C / 25°C | 61 mm | 66% | 12 km/h |
| March | 14°C | 6°C | -4°C / 26°C | 85 mm | 66% | 11 km/h |
| April | 19°C | 11°C | -2°C / 26°C | 122 mm | 67% | 11 km/h |
| May | 23°C | 15°C | 2°C / 30°C | 86 mm | 69% | 10 km/h |
| June | 26°C | 20°C | 10°C / 35°C | 164 mm | 77% | 9 km/h |
| July | 30°C | 24°C | 16°C / 38°C | 109 mm | 77% | 9 km/h |
| August | 32°C | 25°C | 18°C / 41°C | 92 mm | 74% | 10 km/h |
| September | 28°C | 22°C | 12°C / 37°C | 114 mm | 73% | 11 km/h |
| October | 23°C | 15°C | 5°C / 32°C | 71 mm | 68% | 12 km/h |
| November | 18°C | 9°C | 2°C / 44°C | 53 mm | 68% | 11 km/h |
| December | 12°C | 4°C | -6°C / 29°C | 51 mm | 67% | 12 km/h |
Best time to visit Iwakuni
The most comfortable time to visit Iwakuni is generally May to June and October, balancing mild daytime temperatures against the driest stretch of the year. The city has strongly marked seasons and rain concentrates around June, totalling about 1,050 mm a year.
Travellers who prefer heat should aim for August, when highs average 32°C. June is the month to avoid if rain would spoil your plans — it averages 164 mm, roughly 4× the rainfall of the driest month (January).
Source: OpenWeather historical and statistical weather data. Values are long-term averages, not a forecast — see the Iwakuni forecast for what is happening now.