Iwamizawa Weather in September
What's the weather like in Iwamizawa (Hokkaidō) in September 2025?
The climate in Iwamizawa during September can be summarized as mild and wet.
September is in the fall / autumn in Iwamizawa and is typically the 3rd warmest month of the year. Daytime maximum temperatures average around 22°C (71°F), whilst at night 12°C (54°F) is normal.
| Daytime temperature | 21.7°C 71°F |
|---|---|
| Nightly temperature | 12.2°C 53.9°F |
| Average temperature | 16.9°C 62.4°F |
| Daily sunshine | 6 hrs |
| Avg rainfall | 133 mm 5.2 ins |
| Rainy days | 18 days |
| Sea temperature | 20.4°C 68.8°F |
| Humidity | 78% |
| Windspeed | 10.1kph 6 mph |
On average September is the 2nd wettest month of the year in Iwamizawa with around 133mm 5.2 inches of rain making it a wet time to visit. This rainfall is typically spread over 18 days, although this may vary considerably.
On the flip side this corresponds to an average of 6 hours of sunshine per day.
September temperatures in Iwamizawa
September rainfall
September hourly sunshine
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 Iwamizawa in September 2025.
Other monthly averages
Best places to visit in September
Iwamizawa weather stats
| Hottest month: | August | 25.7°C 78.3°F |
|---|---|---|
| Driest month: | March | 61mm 2.4ins |
| Sunniest month: | April | 6.4hrs |
| Coldest month: | January | -2.7°C 27.1°F |
| Wettest month: | August | 154mm 6.1ins |
© Google
Locations nearby
Top Japan locations
- Fukuoka
- Hakodate
- Hakone
- Hiroshima
- Kagoshima
- Kamakura
- Kanazawa
- Kōbe
- Kyoto
- Nagoya
- Naha
- Nara
- Nikkō
- Ōsaka
- Sapporo
- Sendai
- Takayama
- Tokyo
- Yokohama