Click on a day for an hourly weather forecast
The temperatures in Otaru in September are comfortable with low of 12°C and and high up to 21°C.
You can expect about 3 to 8 days of rain in Otaru during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Otaru in September 2025.
If you’re planning to visit Otaru in the near future, we highly recommend that you review the 14 day weather forecast for Otaru before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -3° / -10° | 4 | 1 | 28 | 172 mm | Awful | Otaru in January |
| February | -2° / -10° | 4 | 1 | 25 | 134 mm | Awful | Otaru in February |
| March | 2° / -7° | 7 | 4 | 21 | 125 mm | Awful | Otaru in March |
| April | 8° / -1° | 8 | 15 | 7 | 100 mm | Awful | Otaru in April |
| May | 15° / 5° | 8 | 22 | 0 | 130 mm | Ok | Otaru in May |
| June | 19° / 9° | 8 | 22 | 0 | 161 mm | Ok | Otaru in June |
| July | 24° / 14° | 10 | 21 | 0 | 213 mm | Good | Otaru in July |
| August | 24° / 16° | 11 | 20 | 0 | 253 mm | Good | Otaru in August |
| September | 21° / 12° | 7 | 23 | 0 | 202 mm | Ok | Otaru in September |
| October | 14° / 6° | 8 | 22 | 1 | 149 mm | Ok | Otaru in October |
| November | 7° / -1° | 10 | 8 | 12 | 187 mm | Awful | Otaru in November |
| December | 0° / -7° | 6 | 2 | 26 | 207 mm | Awful | Otaru in December |