Climate averages 1991–2020
Onomichi weather
in August.
A hot, wet month: the warmest and the joint 7th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
August is a hot month in Onomichi: daytime highs average 30.5°C and nights cool to about 24.0°C. By daytime temperature it is the warmest month of the year.
Expect about 107 mm of rain on roughly 11 days, which makes August a wet month (the joint 7th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 13 h 26 min on an average August day.
The nearest other city in this atlas is Mihara (11 km away). In August its highs average 30.9°C, about as warm as Onomichi, with 125 mm of rain.
Among the 303 cities listed in Japan, Onomichi ranks joint 53rd of 303 for the warmest August highs and joint 20th of 303 for the driest August (rainfall, lowest first). The mean August high of those 303 cities is 29.2°C; Onomichi is 1.3°C warmer than that mean.
From August to September, average highs fall by 3.6°C to 26.9°C, and monthly rainfall rises from 107 mm to 145 mm.
The annual picture
August 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, selected | 30.5°C24.0°C | 24.0°C | 107 | 10.8 | 13.413 h |
| September | 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
August in nearby cities
- Mihara in AugustJapan · 11 kmHigh 30.9°C · Low 24.3°C · 125 mm rain
- Fukuyama in AugustJapan · 17 kmHigh 31.0°C · Low 24.4°C · 107 mm rain
- Higashihiroshima in AugustJapan · 42 kmHigh 29.6°C · Low 23.1°C · 132 mm rain
- Imabari in AugustJapan · 43 kmHigh 29.7°C · Low 25.0°C · 142 mm rain
- Niihama in AugustJapan · 52 kmHigh 30.6°C · Low 24.8°C · 151 mm rain
- Kurashiki in AugustJapan · 55 kmHigh 30.7°C · Low 24.6°C · 95 mm rain
- Marugame in AugustJapan · 56 kmHigh 29.4°C · Low 24.5°C · 106 mm rain
- Saijō in AugustJapan · 56 kmHigh 31.3°C · Low 25.2°C · 151 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.