September 21 is generally a great time to visit Dublin. While there is a slight chance of rain (22%), showers are usually brief. Expect comfortable 16°C weather. As it's peak season for Dublin, we recommend booking your stay well in advance to secure the best rates.
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Essential Travel Info for Dublin
Currency
EUR
€ Euro
Language
English
+1 more
Driving
Left side
Connect
As of July 2024, all of the city and its...
Safety
Very High Safety
GPI: 1.288
Dublin Weather Forecast for September 21
"Mild & Comfortable. Expect average highs of 16.2°C. 22% chance of rain."
What to Wear in Dublin in September
Based on historical data for September 21, Dublin typically experiences temperatures between 10.6°C and 16.2°C. We recommend packing light jacket, long pants to stay comfortable. Trends suggest it will stay mostly dry (22% rain probability), but checking the forecast before heading out is always wise.
Complete Packing Guide
Weekly breakdown & essential items for Dublin
Smart Suitcase
- Light Jacket
- Long Pants
Average High
16.2°C
Daytime Peak
Average Low
10.6°C
Nighttime Low
Feels Like
16.2°C
🌤️ Feels accurate
Rain Chance
22%
Avg 1.2mm if it rains
Cloud Cover
69%
Overcast
Pressure
1015.5 hPa
High volatility
Dublin Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 84% 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
🔴 42 min to burn
Type III-IV
🟡 63 min to burn
Type V-VI
🟢 105 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
12.9°C
Pleasant
Heat Stress
Low
No heat warning
🙂 Best outdoor time:
Any time during daylight hours
Marine Conditions
Marine Life
No special warnings. Enjoy the swim!
Swim Index
❄️ Cold Water Hazard
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in Ireland
Flight Traffic
High
93/100 pressure index
Health Advisory
Required
1 vaccine • View Details →
Landing Slots
~385
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Dublin
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
06:09
☀️ Noon
12:19
🌇 Sunset
18:29
⏱️ Daylight
12h 19m
Wind Speed
20.2 km/h
Moderate wind
Sunshine
7.6 hrs
Direct Sun (Cloud-free)
Humidity
81%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Dublin
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 Dublin
Travel Comfort Index
Real-time tourism conditions
Weather Quality
☀️ Excellent
Tourist Crowds
🟡 Busy
Price Level
💰💰💰 Expensive
Health & Wellbeing
Meteo-Health Forecast
Rapid pressure changes detected. High risk for meteosensitive people.
Weather unlikely to affect joint pain.
Fish are active due to pressure changes.
Air quality is excellent. Perfect for outdoor activities.
Regional Safety Profile
Seismic Activity
Zero seismic activity detected in 30 years.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Dublin on September 21 averages 16.2°C with a 22% precipitation probability. Wedding/Outdoor Event Score: 89/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Dublin Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Compare Other Cities
Same date (September 21) in other destinations
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🌍 Explore the same date in different destinations around the world
📍 Is Dublin Worth Visiting on September 21?
Planning a trip to Dublin on September 21? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year is characterized by pleasant mild weather averaging 16.2°C with a 22% historical precipitation risk.
✈️ Travel Logistics: Approximately 385 landing slots available daily during this period, indicating manageable crowd levels.
💉 Health Advisory: 6 vaccinations are recommended for Ireland, including COVID-19.
🌊 Coastal Conditions: Water temperature averages 14.8°C (polar plunge). Wave conditions are generally fun waves with heights around 0.95m.
📊 Historical Extremes: The hottest September 21 recorded in the last 30 years saw temperatures hit 20.5°C in 2019, while the coldest dropped to 6.7°C in 2025.