Nagasaki weather in September
Temperature, sea and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Good
Best time to visit: April – May, September – November
What is the weather like in Nagasaki in September?
In September, Nagasaki is hot: daytime highs average 27 °C, and even at night it stays warm at around 23 °C. The sea averages 26.9 °C – lovely and warm for swimming. Expect around 6 hours of sunshine a day. Rain is frequent, with about 13 rainy days and 196 mm in total. The air is often humid and muggy. All in all, September is a good month for a holiday in Nagasaki.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 58 | 71 | 81 |
| Day | 29° | 27° | 23° |
| Night | 26° | 23° | 19° |
| Sea | 28° | 27° | 24° |
| Sun | 7 h | 6 h | 6 h |
| Rain days | 14 | 13 | 8 |
More details for September
- Daylight
- 12 h 25 min06:03 – 18:28
- UV index
- 8 · very highclear sky, noon (estimate)All months
- Muggy days
- 25 daysdew point 18 °C or moreAll months
- Wind
- 20 km/haverage daily peakAll months
- Cloud cover
- 56 %on averageAll months
- Hot days
- 2 days30 °C or moreAll months
- Snow days
- 0 days1 cm or more of fresh snow
- Time zone
- UTC+9Asia/Tokyo
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %45 %
- Few rainy daysweight 30 %39 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Swimwear
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
- Insect repellent
- Rain jacket or umbrella
Nagasaki in September: quick answers
Is Nagasaki hot in September?
Yes. In September, Nagasaki is hot: daytime highs average 27 °C and nights stay around 23 °C. On about 2 days the thermometer climbs to 30 °C or more.
Can you swim in Nagasaki in September?
Yes. In September the sea averages 26.9 °C – lovely and warm for swimming.
Does it rain much in Nagasaki in September?
Rain is frequent, with about 13 rainy days and 196 mm in total.
Nagasaki month by month
The whole year in NagasakiAll destinations: JapanWhere to go in SeptemberSea temperature in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences