Hiroshima Weather in September

Hiroshima in the first half of September can still be described as a bit hot, but in the second half, it turns warm during the daytime and cool during the nighttime. The rainfall is moderate and mainly in the form of showers, but typhoons may occur.
See also: Japan Weather in September

Temperature

Though stepping into autumn, Hiroshima is still a little hot in the first half of September, when the daily high and low temperatures are usually above 30°C (86°F) and 25°C (75°F), respectively. Then, in general, the temperature drops in the second half. At that time, the daily high ranges from 25°C (75°F) to 30°C (86°F), a warm but no longer hot level; and the daily low is mostly around 20°C (68°F), meaning that it may even be relatively cool in the morning and at night.

Floating Otorii Gate of Itsukushima Shrine

Still a Bit Hot September

But the weather can be different from one year to another. For instance, in 2023 and 2024, the weather was hotter than normal, and the highest temperature was above 30 degrees Celsius (86 degrees Fahrenheit) on most days of the month. So you’d better check the weather forecast to confirm the real-time climate before you go to Hiroshima in September 2026 to determine what to wear.

Rainfall & Humidity

September in Hiroshima typically sees an average rainfall of 168 mm and around 10 rainy days. Fortunately, September’s rain usually falls as short-lived light to moderate showers or thunderstorms, and the sky clears up quickly afterward. So, you don’t need to worry that it will influence your trip a lot.

Overall Sunny September of Hiroshima

Average humidity stands at 68% this month. In the first half month, when temperatures usually exceed 30°C (86°F), this level can make the weather of Hiroshima muggy. By month’s end, however, as temperatures drop, this humidity level typically makes the air fresh.

Typhoon Season

Hiroshima remains vulnerable to typhoon impacts in September. Should a typhoon bringing heavy rain and strong winds come, outdoor activities will likely be disrupted - not only due to transportation disruptions but also for safety reasons.

Hiroshima after a Typhoon

Miyajima Island

Daylight Hours & Sunshine Hours

At the beginning of the month, sunrise and sunset occur around 05:43 and 18:36, respectively. By month’s end, these times shift to 06:04 and 17:55. Consequently, daylight hours gradually shorten from 12.5 to 11.5 hours. However, this doesn’t mean you will have more available daylight hours if you visit Hiroshima in early September - after all, midday hours are quite hot at the beginning of the month, and you may have to avoid outdoor activities during this period.

Average sunshine hours are about 5.5 per day, so you can expect many sunny moments during your trip. UV levels remain relatively strong in September, so if you plan to spend extended periods under the sun, it’s advisable to take sun protection measures, especially during the first half of the month.

One of the Best Months to Visit Hiroshima

September sees Hiroshima gradually shedding the summer heat, with clear skies becoming the norm. Moreover, this period marks the city’s off-season, offering a quiet atmosphere at various attractions. Whether strolling through Hiroshima Peace Memorial Park or taking a boat trip to Miyajima Island for sightseeing, this month proves ideal. Additionally, it’s worth noting that while enjoying the pleasant weather and tranquil scenery, you won’t have to worry about spending a lot in this slack season.

Atomic Bomb Dome View in September

Packing List for Hiroshima Trip in September

Clothes: In early September, you can still wear some summer clothes like T-shirts or short shirts together with light pants. Then, in the second half of the month, you should put on a thin shirt or thin jacket outside the T-shirts or short shirts, and match the tops with jeans or sweatpants, especially in the mornings and evenings.

Shoes: Taking the climate of Hiroshima and your possible activities into consideration, thin sneakers and walking shoes are recommended.

Others: A cap and sunglasses to protect you from the UV rays are recommended to bring. Besides, don’t forget to pack an umbrella with you.

Recommendations and Tips for Hiroshima Trip in September

1. If you are available in the entire September, the latter half of the month with cooler temperatures is an even better time to visit Hiroshima.
2. In 2026, Hiroshima may see a small surge in tourist numbers during September 14-16, a public holiday in Japan. If you prefer quiet, avoid this period; if you are OK with the crowds, make bookings in advance to ensure a smooth trip.
3. Book hotels that can be canceled for free and frequently check the weather forecast before and during your trip, so that you can take timely measures if a typhoon is about to hit Hiroshima.
4. Beyond visiting cultural landmarks like Hiroshima Peace Memorial Park, the Atomic Bomb Dome, and Hiroshima Castle, and enjoying natural scenery at Miyajima Island and Shukkeien Garden, you can also add the Hiroshima Oktoberfest to your September itinerary: Held annually in late September at Hiroshima Gate Park Plaza near the Atomic Bomb Dome, this event can provide you with over 50 varieties of German beer and authentic German cuisine. Additionally, live music performances add to the lively atmosphere.