Kumamoto weather in September
September in Kumamoto: sweltering, soaked, with clean air — a gamble, with 14 rainy days.
Updated September 2026 · climate normals from ERA5 reanalysis
#9 of 12 months in Kumamoto · #1097 of 1413 destinations to visit in September · comfort 62/100 (tier C)
- Days
- 31°C
- Nights
- 22°C
- Wet days
- 14
- Sun
- 8 h
- Humidity
- 82%
- Daylight
- 12 h
Traveller notes on Kumamoto in September
Other months in Kumamoto
Forum posters describe April across Japan as genuinely one of the best months to visit, though variable - a light anorak or jacket is recommended for cooler days and evenings, while sunny stretches can push temperatures into the mid-20sC, warranting layers that can come off as needed. Posters specifically recommend early April in northern Kyushu, including Kumamoto alongside Saga, Oita and Fukuoka, as a strong window for cherry blossoms. Posters generally note April doesn't require a heavy winter coat anywhere in Japan by this point in spring, distinguishing it clearly from the colder months just prior. Posters generally rate April as mild, changeable but genuinely rewarding for Kumamoto, sakura season a real seasonal highlight worth timing a visit around.
Forum posters call October broadly one of Japan's best travel months - warm days, cool nights, and even when a typhoon passes through, rain typically clears within a day or two back to clear blue skies rather than settling in. Early October can still run a touch warm, cooling noticeably by the end of the month. For Kumamoto specifically, posters note some tourist attractions may still be under restoration or closed depending on the year, but the castle grounds remain walkable and Suizenji Garden stays open regardless, giving visitors a reliable core itinerary even if other sites are affected.
Add your own note from Kumamoto's card on the map.
Kumamoto climate normals — September
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Kumamoto in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
BusyFujisaki Hachimangu autumn festival, school holidays in 3 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Kumamoto's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Fair weatherKumamoto's best weather comes in April, October and November — separate windows, not one continuous season.
Best weatherFair weatherToughest weather
What's on in Kumamoto in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Hazard
Mount Aso crater alerts
1 Jan – 31 DecVolcanic activityClosuresNakadake is the day trip everyone books and the one that gets cancelled: the crater rim closes without notice on gas readings or a raised alert, and has been shut for long stretches. Check before you drive out. Source ↗
- Hazard
Typhoon season
1 Aug – 30 Sep · usuallyClosuresKyushu takes more direct hits than anywhere else in Japan and a landfall stops the trains and the airport for a day. Storms are not spread evenly through the year and these are the two months. Source ↗
- Festival
Fujisaki Hachimangu autumn festival
10–20 Sep · usuallyReligious feastCrowdedThe city's own festival, run around decorated horses and a drumming crowd that walks them through the centre for hours. Roads shut and the whole place turns out for it. Source ↗
Nearby, and something's on
Within 300 km of Kumamoto — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Kumamoto?
Kumamoto in September — FAQ
- Is September a good time to visit Kumamoto?
- September in Kumamoto: sweltering, soaked, with clean air — a gamble, with 14 rainy days. It ranks #9 of 12 months for Kumamoto on SeasonMap's comfort score (62/100).
- What is the weather like in Kumamoto in September?
- In September, Kumamoto averages a daily high of 30.5°C and a low of 22°C, with about 165.9 mm of rain over roughly 13.5 rainy days.
- What is the air quality in Kumamoto in September?
- Kumamoto has a mean US Air Quality Index of about 47 in September.
Within 300 km: Hiroshima's Miyajima visitor tax on 1 Jan – 31 Dec, and Busan's Chuseok on 24–26 Sep.