Climate averages 1991–2020
Yachiyo weather
in September.
A warm, 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 Yachiyo: daytime highs average 26.0°C and nights cool to about 20.5°C. By daytime temperature it is the 3rd warmest of the 12 months.
Expect about 175 mm of rain on roughly 14 days, which makes September a wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 26 min on an average September day.
The nearest other city in this atlas is Narashino (10 km away). In September its highs average 26.1°C, about as warm as Yachiyo, with 175 mm of rain.
Among the 303 cities listed in Japan, Yachiyo ranks joint 159th of 303 for the warmest September highs and joint 95th of 303 for the driest September (rainfall, lowest first). The mean September high of those 303 cities is 25.7°C; Yachiyo is 0.4°C warmer than that mean.
From September to October, average highs fall by 5.3°C to 20.7°C, and monthly rainfall rises from 175 mm to 207 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
Yachiyo climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 8.3°C1.0°C | 1.0°C | 69 | 6.8 | 10.010 h |
| February | 9.1°C1.4°C | 1.4°C | 66 | 8.0 | 10.911 h |
| March | 12.4°C4.5°C | 4.5°C | 120 | 12.2 | 11.912 h |
| April | 17.2°C9.3°C | 9.3°C | 114 | 11.9 | 13.113 h |
| May | 21.6°C14.3°C | 14.3°C | 131 | 11.6 | 14.014 h |
| June | 24.5°C18.1°C | 18.1°C | 161 | 13.7 | 14.515 h |
| July | 28.2°C22.1°C | 22.1°C | 153 | 13.7 | 14.314 h |
| August | 29.6°C23.5°C | 23.5°C | 112 | 11.8 | 13.514 h |
| September, selected | 26.0°C20.5°C | 20.5°C | 175 | 14.2 | 12.412 h |
| October | 20.7°C15.0°C | 15.0°C | 207 | 12.9 | 11.311 h |
| November | 15.7°C9.3°C | 9.3°C | 98 | 10.1 | 10.310 h |
| December | 10.7°C3.8°C | 3.8°C | 63 | 7.7 | 9.810 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
- Narashino in SeptemberJapan · 10 kmHigh 26.1°C · Low 20.5°C · 175 mm rain
- Sakura in SeptemberJapan · 10 kmHigh 26.2°C · Low 20.6°C · 175 mm rain
- Inzai in SeptemberJapan · 12 kmHigh 26.2°C · Low 20.2°C · 175 mm rain
- Kamagaya in SeptemberJapan · 12 kmHigh 26.2°C · Low 20.1°C · 175 mm rain
- Chiba in SeptemberJapan · 15 kmHigh 26.1°C · Low 20.9°C · 207 mm rain
- Narita in SeptemberJapan · 18 kmHigh 26.3°C · Low 20.2°C · 175 mm rain
- Toride in SeptemberJapan · 19 kmHigh 26.3°C · Low 20.0°C · 167 mm rain
- Ryūgasaki in SeptemberJapan · 19 kmHigh 26.3°C · Low 20.1°C · 168 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 Yachiyo) is explained once on the Yachiyo year overview and on the Sources, method and limits page.
Matsudo, Kashiwa and Nagareyama lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.