Climate averages 1991–2020
Yamaguchi 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 Yamaguchi: daytime highs average 26.7°C and nights cool to about 19.6°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 178 mm of rain on roughly 12 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 Hōfu (17 km away). In September its highs average 27.1°C, about as warm as Yamaguchi, with 156 mm of rain.
Among the 303 cities listed in Japan, Yamaguchi ranks joint 83rd of 303 for the warmest September highs and joint 113th of 303 for the driest September (rainfall, lowest first). The mean September high of those 303 cities is 25.7°C; Yamaguchi is 1.0°C warmer than that mean.
From September to October, average highs fall by 5.1°C to 21.6°C, and monthly rainfall falls from 178 mm to 97 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
Yamaguchi climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 7.7°C1.5°C | 1.5°C | 61 | 9.7 | 10.210 h |
| February | 9.0°C1.6°C | 1.6°C | 72 | 10.0 | 10.911 h |
| March | 12.7°C4.0°C | 4.0°C | 117 | 11.4 | 11.912 h |
| April | 17.9°C8.4°C | 8.4°C | 130 | 10.6 | 13.013 h |
| May | 22.4°C13.2°C | 13.2°C | 150 | 10.5 | 13.914 h |
| June | 25.6°C17.9°C | 17.9°C | 248 | 14.3 | 14.414 h |
| July | 28.8°C22.3°C | 22.3°C | 283 | 16.3 | 14.214 h |
| August | 30.2°C23.4°C | 23.4°C | 167 | 14.2 | 13.413 h |
| September, selected | 26.7°C19.6°C | 19.6°C | 178 | 12.4 | 12.412 h |
| October | 21.6°C13.7°C | 13.7°C | 97 | 8.1 | 11.411 h |
| November | 15.7°C8.3°C | 8.3°C | 78 | 8.2 | 10.410 h |
| December | 10.0°C3.6°C | 3.6°C | 64 | 9.7 | 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
September in nearby cities
- Hōfu in SeptemberJapan · 17 kmHigh 27.1°C · Low 20.7°C · 156 mm rain
- Ube in SeptemberJapan · 33 kmHigh 26.4°C · Low 21.4°C · 161 mm rain
- Shūnan in SeptemberJapan · 35 kmHigh 25.1°C · Low 19.0°C · 169 mm rain
- Yukuhashi in SeptemberJapan · 67 kmHigh 26.7°C · Low 20.8°C · 157 mm rain
- Kitakyushu in SeptemberJapan · 68 kmHigh 26.2°C · Low 21.2°C · 162 mm rain
- Iwakuni in SeptemberJapan · 69 kmHigh 26.5°C · Low 20.9°C · 185 mm rain
- Nakatsu in SeptemberJapan · 70 kmHigh 27.1°C · Low 21.1°C · 167 mm rain
- Hatsukaichi in SeptemberJapan · 82 kmHigh 27.3°C · Low 20.5°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 Yamaguchi) is explained once on the Yamaguchi year overview and on the Sources, method and limits page.