September 18 is generally a great time to visit Hiroshima. While there is a slight chance of rain (36%), showers are usually brief. Expect comfortable 28°C weather. As it's peak season for Hiroshima, we recommend booking your stay well in advance to secure the best rates.
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Essential Travel Info for Hiroshima
Currency
JPY
¥ Japanese yen
Language
Japanese
Driving
Left side
Connect
Public wireless LAN is available at publ...
Safety
Very High Safety
GPI: 1.336
Hiroshima Weather Forecast for September 18
"Warm & Sunny. Expect average highs of 27.5°C. 36% chance of rain."
What to Wear in Hiroshima in September
Based on historical data for September 18, Hiroshima typically experiences temperatures between 20.7°C and 27.5°C. We recommend packing t-shirt, light clothing, umbrella to stay comfortable. With a 36% chance of rain, keeping a raincoat or umbrella handy is a smart move.
Complete Packing Guide
Weekly breakdown & essential items for Hiroshima
Smart Suitcase
- T-Shirt
- Light Clothing
- Umbrella
Average High
27.5°C
Daytime Peak
Average Low
20.7°C
Nighttime Low
Feels Like
30.9°C
🔥 Feels warmer
Rain Chance
36%
Avg 4mm if it rains
Cloud Cover
61%
Overcast
Pressure
1012.1 hPa
Medium volatility
Hiroshima Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 85% of the time. Safe to plan outdoor activities with confidence.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 15 for extended outdoor time
Type I-II
🔴 29 min to burn
Type III-IV
🟡 44 min to burn
Type V-VI
🟢 73 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
23.7°C
Humid/Sticky
Heat Index
30.9°C
Feels hotter
😐 Best outdoor time:
Morning hours (before 11 AM)
Marine Conditions
Jellyfish Warning
High water temps may attract jellyfish swarms.
Swim Index
✅ Excellent Swimming Conditions
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in Japan
Flight Traffic
High
90/100 pressure index
Health Advisory
Required
1 vaccine • View Details →
Landing Slots
~26
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Hiroshima
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:56
☀️ Noon
12:05
🌇 Sunset
18:15
⏱️ Daylight
12h 19m
Wind Speed
12.3 km/h
Gentle breeze
Sunshine
8.5 hrs
Direct Sun (Cloud-free)
Humidity
80%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Hiroshima
Smart Flight Estimator
Airport-to-Airport Logistics
unlock smart flight estimates
Add your home location in settings to see airport details.
Travel Health & Safety in Hiroshima
Travel Comfort Index
Real-time tourism conditions
Weather Quality
⛅ Good
Tourist Crowds
🟡 Busy
Price Level
💰💰💰 Expensive
Health & Wellbeing
Meteo-Health Forecast
Moderate fluctuations. Some sensitivity possible.
Mild discomfort possible for arthritic conditions.
Moderate fish activity expected.
Air quality is acceptable. Sensitive individuals should limit prolonged outdoor exertion.
Regional Safety Profile
Seismic Activity
Moderate seismic activity. Occasional tremors possible.
Typhoon Risk
Year-round risk present
Travel Alert: This region has elevated natural risks. We recommend registering with your embassy and keeping emergency numbers handy.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Hiroshima on September 18 averages 27.5°C with a 36% precipitation probability. Wedding/Outdoor Event Score: 90/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Hiroshima Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Better Alternatives Nearby
Consider these dates within ±7 days
September 21
26.4°C • 28% rain
Score
95
September 23
26.1°C • 27% rain
Score
95
September 24
26.1°C • 26% rain
Score
95
💡 Moving your event by a few days could significantly improve weather conditions
Compare Other Cities
Same date (September 18) in other destinations
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📍 Is Hiroshima Worth Visiting on September 18?
Planning a trip to Hiroshima on September 18? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year typically offers vibrant summer conditions averaging 27.5°C with a 36% historical precipitation risk.
✈️ Travel Logistics: Approximately 26 landing slots available daily during this period, indicating manageable crowd levels.
💉 Health Advisory: 8 vaccinations are recommended for Japan, including COVID-19.
🌊 Coastal Conditions: Water temperature averages 28.5°C (tropical bath). Wave conditions are generally lake-like with heights around 0.31m.
📊 Historical Extremes: The hottest September 18 recorded in the last 30 years saw temperatures hit 31.5°C in 2024, while the coldest dropped to 17.3°C in 2017.