Climate averages 1991–2020
Iwaki weather
in September.
A warm, very 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 warm month in Iwaki: daytime highs average 24.5°C and nights cool to about 19.4°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 192 mm of rain on roughly 14 days, which makes September a very wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 27 min on an average September day.
The nearest other city in this atlas is Sukagawa (51 km away). In September its highs average 23.7°C, 0.8°C cooler than Iwaki, with 171 mm of rain.
Among the 303 cities listed in Japan, Iwaki ranks joint 248th of 303 for the warmest September highs and joint 168th of 303 for the driest September (rainfall, lowest first). The mean September high of those 303 cities is 25.7°C; Iwaki is 1.2°C cooler than that mean.
From September to October, average highs fall by 4.9°C to 19.6°C, and monthly rainfall rises from 192 mm to 223 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
Iwaki climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 6.9°C1.1°C | 1.1°C | 71 | 7.9 | 9.910 h |
| February | 7.4°C0.8°C | 0.8°C | 69 | 8.0 | 10.811 h |
| March | 10.7°C3.1°C | 3.1°C | 125 | 12.1 | 11.912 h |
| April | 15.5°C7.7°C | 7.7°C | 134 | 11.9 | 13.113 h |
| May | 19.8°C12.6°C | 12.6°C | 145 | 12.0 | 14.114 h |
| June | 22.6°C16.8°C | 16.8°C | 146 | 13.7 | 14.715 h |
| July | 26.0°C20.7°C | 20.7°C | 175 | 14.5 | 14.414 h |
| August | 27.5°C22.3°C | 22.3°C | 126 | 11.8 | 13.614 h |
| September, selected | 24.5°C19.4°C | 19.4°C | 192 | 14.1 | 12.512 h |
| October | 19.6°C14.1°C | 14.1°C | 223 | 13.4 | 11.311 h |
| November | 14.6°C8.3°C | 8.3°C | 111 | 9.8 | 10.210 h |
| December | 9.4°C3.5°C | 3.5°C | 73 | 8.6 | 9.710 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
- Sukagawa in SeptemberJapan · 51 kmHigh 23.7°C · Low 16.8°C · 171 mm rain
- Hitachi in SeptemberJapan · 54 kmHigh 24.7°C · Low 20.1°C · 174 mm rain
- Kōriyama in SeptemberJapan · 59 kmHigh 23.7°C · Low 16.8°C · 151 mm rain
- Nasushiobara in SeptemberJapan · 73 kmHigh 23.8°C · Low 17.0°C · 227 mm rain
- Ōtawara in SeptemberJapan · 78 kmHigh 24.0°C · Low 17.0°C · 193 mm rain
- Hitachi-Naka in SeptemberJapan · 79 kmHigh 24.6°C · Low 19.9°C · 179 mm rain
- Fukushima in SeptemberJapan · 86 kmHigh 24.1°C · Low 16.9°C · 169 mm rain
- Mito in SeptemberJapan · 87 kmHigh 25.1°C · Low 19.6°C · 176 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 Iwaki) is explained once on the Iwaki year overview and on the Sources, method and limits page.