Climate averages 1991–2020
Onomichi weather
in September.
A warm, wet month: the 3rd warmest and the 10th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in Onomichi: daytime highs average 26.9°C and nights cool to about 20.3°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 145 mm of rain on roughly 11 days, which makes September a wet month (the 10th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 25 min on an average September day.
The nearest other city in this atlas is Mihara (11 km away). In September its highs average 27.3°C, about as warm as Onomichi, with 160 mm of rain.
Among the 303 cities listed in Japan, Onomichi ranks joint 67th of 303 for the warmest September highs and joint 18th of 303 for the driest September (rainfall, lowest first). The mean September high of those 303 cities is 25.7°C; Onomichi is 1.2°C warmer than that mean.
From September to October, average highs fall by 5.4°C to 21.5°C, and monthly rainfall falls from 145 mm to 105 mm.
The annual picture
September in context
Monthly rainfall
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
Onomichi climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 8.5°C1.5°C | 1.5°C | 42 | 5.7 | 10.110 h |
| February | 9.6°C1.6°C | 1.6°C | 54 | 7.2 | 10.911 h |
| March | 12.9°C4.2°C | 4.2°C | 92 | 9.7 | 11.912 h |
| April | 17.9°C8.9°C | 8.9°C | 107 | 9.6 | 13.013 h |
| May | 22.4°C13.8°C | 13.8°C | 124 | 10.0 | 13.914 h |
| June | 25.3°C18.4°C | 18.4°C | 182 | 12.0 | 14.414 h |
| July | 28.8°C22.8°C | 22.8°C | 189 | 13.6 | 14.214 h |
| August | 30.5°C24.0°C | 24.0°C | 107 | 10.8 | 13.413 h |
| September, selected | 26.9°C20.3°C | 20.3°C | 145 | 10.7 | 12.412 h |
| October | 21.5°C14.3°C | 14.3°C | 105 | 7.3 | 11.311 h |
| November | 16.0°C8.6°C | 8.6°C | 55 | 6.1 | 10.410 h |
| December | 10.7°C3.8°C | 3.8°C | 47 | 5.6 | 9.910 h |
Rainfall is the average of the 30 separate monthly totals. A rain 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
- Mihara in SeptemberJapan · 11 kmHigh 27.3°C · Low 20.4°C · 160 mm rain
- Fukuyama in SeptemberJapan · 17 kmHigh 27.3°C · Low 20.6°C · 145 mm rain
- Higashihiroshima in SeptemberJapan · 42 kmHigh 26.2°C · Low 19.3°C · 169 mm rain
- Imabari in SeptemberJapan · 43 kmHigh 26.5°C · Low 21.9°C · 196 mm rain
- Niihama in SeptemberJapan · 52 kmHigh 27.1°C · Low 21.4°C · 216 mm rain
- Kurashiki in SeptemberJapan · 55 kmHigh 27.1°C · Low 20.9°C · 153 mm rain
- Marugame in SeptemberJapan · 56 kmHigh 25.9°C · Low 21.1°C · 168 mm rain
- Saijō in SeptemberJapan · 56 kmHigh 27.7°C · Low 21.7°C · 216 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 Onomichi) is explained once on the Onomichi year overview and on the Sources, method and limits page.
Fukuyama lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.