Climate averages 1991–2020
Tomakomai 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 Tomakomai: daytime highs average 20.1°C and nights cool to about 15.1°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 177 mm of rain on roughly 15 days, which makes September a wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 32 min on an average September day.
The nearest other city in this atlas is Chitose (21 km away). In September its highs average 20.4°C, about as warm as Tomakomai, with 137 mm of rain.
Among the 303 cities listed in Japan, Tomakomai ranks 300th of 303 for the warmest September highs and 112th of 303 for the driest September (rainfall, lowest first). The mean September high of those 303 cities is 25.7°C; Tomakomai is 5.6°C cooler than that mean.
From September to October, average highs fall by 5.7°C to 14.3°C, and monthly rainfall falls from 177 mm to 110 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
Tomakomai climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -2.0°C-7.5°C | -7.5°C | 44 | 7.1 | 9.49 h |
| February | -1.3°C-7.4°C | -7.4°C | 44 | 7.4 | 10.511 h |
| March | 2.2°C-4.0°C | -4.0°C | 63 | 10.3 | 11.912 h |
| April | 7.5°C1.0°C | 1.0°C | 78 | 11.5 | 13.413 h |
| May | 12.7°C6.7°C | 6.7°C | 109 | 11.8 | 14.615 h |
| June | 16.7°C11.6°C | 11.6°C | 100 | 11.3 | 15.315 h |
| July | 20.6°C16.1°C | 16.1°C | 138 | 13.7 | 15.015 h |
| August | 22.5°C18.2°C | 18.2°C | 197 | 14.5 | 13.914 h |
| September, selected | 20.1°C15.1°C | 15.1°C | 177 | 15.0 | 12.513 h |
| October | 14.3°C8.8°C | 8.8°C | 110 | 11.8 | 11.111 h |
| November | 7.3°C2.0°C | 2.0°C | 78 | 10.8 | 9.810 h |
| December | 0.7°C-4.2°C | -4.2°C | 63 | 8.7 | 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
- Chitose in SeptemberJapan · 21 kmHigh 20.4°C · Low 14.2°C · 137 mm rain
- Eniwa in SeptemberJapan · 29 kmHigh 20.4°C · Low 13.6°C · 138 mm rain
- Sapporo in SeptemberJapan · 52 kmHigh 20.9°C · Low 14.7°C · 155 mm rain
- Ebetsu in SeptemberJapan · 53 kmHigh 20.5°C · Low 13.5°C · 138 mm rain
- Muroran in SeptemberJapan · 62 kmHigh 20.2°C · Low 15.6°C · 166 mm rain
- Iwamizawa in SeptemberJapan · 64 kmHigh 20.8°C · Low 13.1°C · 126 mm rain
- Otaru in SeptemberJapan · 79 kmHigh 20.8°C · Low 15.3°C · 149 mm rain
- Hakodate in SeptemberJapan · 119 kmHigh 21.3°C · Low 16.9°C · 185 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 Tomakomai) is explained once on the Tomakomai year overview and on the Sources, method and limits page.