Climate averages 1991–2020
Otaru weather
in September.
A mild, wet month: the 3rd warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Otaru: daytime highs average 20.8°C and nights cool to about 15.3°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 149 mm of rain on roughly 14 days, which makes September a wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 33 min on an average September day.
The nearest other city in this atlas is Sapporo (31 km away). In September its highs average 20.9°C, about as warm as Otaru, with 155 mm of rain.
Among the 303 cities listed in Japan, Otaru ranks joint 293rd of 303 for the warmest September highs and joint 24th of 303 for the driest September (rainfall, lowest first). The mean September high of those 303 cities is 25.7°C; Otaru is 4.9°C cooler than that mean.
From September to October, average highs fall by 6.4°C to 14.4°C, and monthly rainfall falls from 149 mm to 117 mm.
The annual picture
September in context
Monthly precipitation
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
Otaru climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -2.3°C-5.8°C | -5.8°C | 98 | 20.8 | 9.49 h |
| February | -1.6°C-5.7°C | -5.7°C | 80 | 18.2 | 10.510 h |
| March | 1.8°C-3.0°C | -3.0°C | 76 | 15.0 | 11.912 h |
| April | 7.3°C1.4°C | 1.4°C | 66 | 11.2 | 13.413 h |
| May | 15.1°C7.0°C | 7.0°C | 84 | 11.7 | 14.615 h |
| June | 19.6°C12.2°C | 12.2°C | 76 | 10.6 | 15.315 h |
| July | 23.5°C17.0°C | 17.0°C | 127 | 12.8 | 15.015 h |
| August | 24.4°C18.8°C | 18.8°C | 163 | 14.1 | 14.014 h |
| September, selected | 20.8°C15.3°C | 15.3°C | 149 | 13.9 | 12.513 h |
| October | 14.4°C9.0°C | 9.0°C | 117 | 14.9 | 11.111 h |
| November | 6.8°C2.3°C | 2.3°C | 129 | 18.6 | 9.810 h |
| December | 0.3°C-2.7°C | -2.7°C | 125 | 21.9 | 9.19 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet 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
September in nearby cities
- Sapporo in SeptemberJapan · 31 kmHigh 20.9°C · Low 14.7°C · 155 mm rain
- Ebetsu in SeptemberJapan · 45 kmHigh 20.5°C · Low 13.5°C · 138 mm rain
- Eniwa in SeptemberJapan · 57 kmHigh 20.4°C · Low 13.6°C · 138 mm rain
- Iwamizawa in SeptemberJapan · 61 kmHigh 20.8°C · Low 13.1°C · 126 mm rain
- Chitose in SeptemberJapan · 67 kmHigh 20.4°C · Low 14.2°C · 137 mm rain
- Tomakomai in SeptemberJapan · 79 kmHigh 20.1°C · Low 15.1°C · 177 mm rain
- Muroran in SeptemberJapan · 97 kmHigh 20.2°C · Low 15.6°C · 166 mm rain
- Asahikawa in SeptemberJapan · 128 kmHigh 19.8°C · Low 11.6°C · 142 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 Otaru) is explained once on the Otaru year overview and on the Sources, method and limits page.