Nagasaki Weather in September

Season: Autumn

In short:
1. The weather of Nagasaki in September is generally hot in the day, but much cooler in the early morning and at night.
2. Precipitation is mainly in forms of light rainfalls, while heavy rain also falls but only a few.
3. Take good sun protection measures since the ultraviolet rays in September are quite strong.
4. Nagasaki is not crowded in September, and travel expenses for accommodation and transportation are comparatively lower.

What Is the Temperature Like in Nagasaki in September?

During September, there is no extensive heat in Nagasaki generally. However, with an average high temperature of 29 degrees Celsius (84.2 degrees Fahrenheit), and the maximum temperature above 31℃ (87.8℉) occupying about 10 days of the month, the weather in the daytime is somehow hot. The average low temperature is 22 ℃ (71.6℉), so it is cool and comfortable in the early morning and after sunset.

Nagasaki in Sunny September

Precipitation & Humidity

Nagasaki, as a coastal city, is never short of rainy weather. There are approximately 17 wet days on average in September, which consists of 2-3 days of moderate or heavy rainfalls and 10 more days of slight rainfalls. The monthly average precipitation is 215 mm.

Naturally, the weather in Nagasaki in September is still humid, with an average humidity of 76%.

Atomic Bomb Hypocenter on Rainy Day

Daylight Hours & Sunshine Hours

As the footsteps of autumn slowly approach in September, the sun rises a little later, at around 6:02 in the morning, and sets a little earlier, at around 18:27. Therefore, in this month, you have an average of 12.4 hours of daylight each day enjoying your trip in Nagasaki.

In terms of the sunshine, its daily average duration is 5.5 hours. Don’t underestimate the ultraviolet rays in the early autumn month. You still may get burnt with the UV index averaging 9.

September: the Typhoon Season in Nagasaki

The typhoon season of Nagasaki generally lasts from June to October. September is one of the months with a high frequency of typhoons. Based on meteorological records, typhoons in September are more destructive and tend to cause heavy rainfalls.

Reasons for Visiting Nagasaki in September

Seaside Hotel in Nagasaki

First of all, there are rare intensively hot days in September and the daytime is relatively long. If you are planning to visit Nagasaki in September, 2026, you have enough day time to enjoy the sightseeing comfortably.

Secondly, summer holiday usually ends at the end of August, so the number of tourists in September will decrease significantly. Accordingly, tourist attractions are not crowded. Besides, the prices of air tickets, scenic spot entrance fees, and hotel rates will all be relatively lower.

What to Bring for Nagasaki Trip in September:

Clothing

The weather during daytime is relatively hot, so you can wear a summer T-shirt on the top and shorts or a skirt at the bottom. However, the temperature in the early morning and at night is much cooler, so you’d better add a thin coat or a long-sleeved shirt outside; also, change your shorts or skirt with light pants or a long dress to protect your joints from being exposed to the cool breeze for a long time.

Shoes
Any shoes that are light and ventilated are recommended. For example, canvas shoes and net-surface sneakers are all suitable choices. For rainy day outings, you need a pair of shoes which are both waterproof and slip-resistant.

Others
Rain gear such as the umbrella or raincoat must never be left behind in view of the frequent rainy weather in September in Nagasaki.

The ultraviolet rays in sunny days are quite strong. Remember to wear sunglasses and apply sunscreen when going out, and bring a parasol and sunbonnet.

What Is the Scenery Like in Nagasaki in September?

Although September is a month of autumn, the natural scenery in Nagasaki is still the same as that in summer. Walking in the Central Park, strolling in the Glover Garden, or climbing the Mount Inasa, you will still be surrounded by lush green trees and vibrant summer scenery. The leaves in Nagasaki usually start to change colors in early November.

Travel Recommendations and Tips

Dejimamachi after Rain shower

Given that the typhoon is very active in September, it is of great importance for you to pay close attention to the weather forecast so as to avoid going to visit Nagasaki in a dangerous period.

In consideration of the fact that your journey may be disturbed by rainfalls, you’d better arrange an alternative schedule for your trip in Nagasaki. For instance, on rainy days, you can replace outdoor sightseeing with indoor visits to places like the Atomic Bomb Museum, the Nagasaki Museum of History & Culture, learning the stories behind this city; if the rain is light, you can, bringing rain gear, visit the Western-style architectural complex in the Dejimamachi and enjoy various exhibits inside.