Nagasaki Weather in September

September in Nagasaki typically sees daytime highs of 28°C (82°F) and nighttime lows of 23°C (73°F). September falls within the rainy season, so heavy rainfall is to be expected. It falls within the summer season.

Rainfall in Nagasaki in September

Nagasaki is in the rainy season in September, with rain on around 17 days and an average of 214 mm (8.4 in). The rainy season here brings regular, substantial showers. It's worth being prepared for rain on most days you're out.

Temperature in Nagasaki in September

In September, Nagasaki sees high temperatures, with highs of 28°C (82°F). Nights drop to around 23°C (73°F). September is typically considered a summer month. Overall, the month follows a fairly predictable daily temperature pattern. Nights are warm at 23°C (73°F). It's worth making sure your accommodation has decent ventilation or air conditioning.

Sunshine in Nagasaki in September

The area experiences a moderate amount of sunshine, with approximately 173 hours of sunlight expected. Even though this month is part of the rainy season, you could still see the sun every now and then.

Wind Speed in Nagasaki in September

Wind speeds average 1 m/s (2 knots) during September. At this speed, you'll experience mostly light air movement that's just barely noticeable. As an average, some days will be completely calm while others have gentle breezes you can feel on your skin.

Average water temperature in September

With water at 26°C (79°F), you can expect warm, pleasant conditions for any water activity. There's no adjustment period — it feels comfortable straight away.

Should you favor a climate that's both dry and comfortably warm, October typically offers the most agreeable circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.

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For a detailed overview over the year and the best time to visit Japan, check out our Nagasaki's climate page.

Nagasaki Temperature in September

Min Temperature 23°C (73°F)  

Max Temperature 28°C (82°F)  

Water Temperature 26°C (79°F)  

Chance of Rain 58%  

Precipitation 214 mm (8.4 in)  

Rainy days 17 days  

Humidity 74%  

Windspeed 1 m/s (2 knots)  

Sunshine 173 hours  

Percentage Sunshine 46%  

Daily Historical Temperatures

50-year average (1976-2025)

Based on our historical records, temperatures in Nagasaki typically drop from around 30°C (86°F) at the start of September to approximately 27°C (81°F) by the end. Nights are warm, with lows typically ranging from 20°C (68°F) to 24°C (75°F).

Average temperatures in September

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Daily Historical Precipitation

50-year average (1976-2025)

Average daily rainfall for each day of the month based on long-term records.

Average precipitation in September

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Historical weather for Nagasaki in September

Browse day-by-day weather records for Nagasaki spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.

Historical weather Temperatures Precipitation

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Nagasaki historical weather extremes in September

Based on weather observations in Nagasaki between 1976 and 2025, these are the recorded extremes during September.

• Nagasaki recorded its highest September temperature of 37°C (99°F) on September 19, 2024.
• The lowest daytime temperature in September was 20°C (68°F), recorded on September 30, 1993.
• The lowest overnight temperature recorded in September was 11°C (52°F) (September 28, 1987).

What to Wear in Nagasaki in September

Warm weather calls for comfortable, breathable clothing in September. Cotton t-shirts, shorts, light dresses, and sandals are perfect. You might still want a light layer for evenings or air-conditioned places (for example buses). Also bring a poncho, it will rain a lot! Waterproof everything you can. With water temperatures around 26°C (79°F), swimming conditions are excellent. Pack your swimsuit, goggles, and maybe some water shoes. Bring sunglasses since you'll have some sunny periods throughout the month

What To Do in Nagasaki in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

7/10

Cycling

7/10

Walking

7/10

Camping

6/10

Outdoor sports

7/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit Japan, check out our Nagasaki's climate page.

More climate data for Nagasaki

Temperature Rainfall Sunshine Humidity Wind Speed Water Temp

See the full Nagasaki climate overview or explore weather in Japan.