Climate averages 1991–2020
Iwakuni weather
in December.
A cool, moderately wet month: the 10th warmest and the 2nd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a cool month in Iwakuni: daytime highs average 10.8°C and nights cool to about 5.1°C. By daytime temperature it is the 10th warmest of the 12 months.
Expect about 60 mm of rain on roughly 7 days, which makes December a moderately wet month (the 2nd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 9 h 55 min on an average December day.
The nearest other city in this atlas is Hatsukaichi (23 km away). In December its highs average 10.6°C, about as warm as Iwakuni, with 60 mm of rain.
Among the 303 cities listed in Japan, Iwakuni ranks joint 90th of 303 for the warmest December highs and joint 73rd of 303 for the driest December (rainfall, lowest first). The mean December high of those 303 cities is 9.5°C; Iwakuni is 1.3°C warmer than that mean.
From December to January, average highs fall by 2.3°C to 8.5°C, and monthly rainfall falls from 60 mm to 50 mm.
The annual picture
December 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
Iwakuni climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 8.5°C2.8°C | 2.8°C | 50 | 6.2 | 10.210 h |
| February | 9.6°C2.8°C | 2.8°C | 69 | 8.0 | 10.911 h |
| March | 13.0°C5.3°C | 5.3°C | 116 | 10.1 | 11.912 h |
| April | 17.8°C9.9°C | 9.9°C | 138 | 9.7 | 13.013 h |
| May | 22.2°C14.8°C | 14.8°C | 158 | 10.3 | 13.914 h |
| June | 25.1°C19.1°C | 19.1°C | 234 | 13.9 | 14.414 h |
| July | 28.7°C23.4°C | 23.4°C | 255 | 15.2 | 14.214 h |
| August | 29.8°C24.4°C | 24.4°C | 169 | 14.4 | 13.413 h |
| September | 26.5°C20.9°C | 20.9°C | 185 | 11.7 | 12.412 h |
| October | 21.5°C15.5°C | 15.5°C | 116 | 8.0 | 11.411 h |
| November | 16.1°C10.1°C | 10.1°C | 72 | 7.1 | 10.410 h |
| December, selected | 10.8°C5.1°C | 5.1°C | 60 | 6.7 | 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
December in nearby cities
- Hatsukaichi in DecemberJapan · 23 kmHigh 10.6°C · Low 4.0°C · 60 mm rain
- Kure in DecemberJapan · 33 kmHigh 10.6°C · Low 5.8°C · 61 mm rain
- Hiroshima in DecemberJapan · 34 kmHigh 10.3°C · Low 3.4°C · 64 mm rain
- Shūnan in DecemberJapan · 37 kmHigh 8.9°C · Low 3.0°C · 69 mm rain
- Higashihiroshima in DecemberJapan · 55 kmHigh 9.7°C · Low 2.6°C · 53 mm rain
- Hōfu in DecemberJapan · 61 kmHigh 10.9°C · Low 5.0°C · 68 mm rain
- Matsuyama in DecemberJapan · 62 kmHigh 11.3°C · Low 5.4°C · 83 mm rain
- Yamaguchi in DecemberJapan · 69 kmHigh 10.0°C · Low 3.6°C · 64 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 Iwakuni) is explained once on the Iwakuni year overview and on the Sources, method and limits page.
Hatsukaichi lies in the same rainfall cell, so its rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.