The climate in Yamaguchi during September can be summarized as warm, humid and very wet.
September is in the fall / autumn in Yamaguchi and is typically the 3rd warmest month of the year. Daytime maximum temperatures average around a muggy 25°C (77°F), whilst at night 18°C (64°F) is normal.
Daytime temperature | 25.1°C 77.2°F |
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Nightly temperature | 17.5°C 63.5°F |
Average temperature | 21.3°C 70.3°F |
Daily sunshine | 5.4 hrs |
Avg rainfall | 203 mm 8 ins |
Rainy days | 17 days |
Sea temperature | 25.7°C 78.3°F |
Humidity | 80% |
Windspeed | 9kph 6 mph |
On average September is the 3rd wettest month of the year in Yamaguchi with around 203mm 8 inches of rain making it a very wet time to visit. This rainfall is typically spread over 17 days, although this may vary considerably.
On the flip side this corresponds to an average of 5.4 hours of sunshine per day.
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Yamaguchi in September 2025.
Best places to visit in September
Hottest month: | August | 28.8°C 83.8°F |
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Driest month: | December | 64mm 2.5ins |
Sunniest month: | October | 5.8hrs |
Coldest month: | January | 6.4°C 43.5°F |
Wettest month: | July | 315mm 12.4ins |