Ireland Dublin Weather in September — Climate Guide
September in Dublin is high
September is high for Dublin.
September is a quietly excellent month — mild early-autumn weather (averaging 17°C/10°C), softening crowds, and the relief of post-peak hotel prices, while days are still reasonably long.
The weather is often pleasant and settled in the first half, gradually turning cooler and wetter toward October. Layers and a waterproof remain the rule, but you'll get plenty of mild, walkable days.
Travel score
Dublin September Weather Stats
Avg High
17°C
Avg Low
10°C
Rainy Days
11
65mm total
Sunshine
4.2h
Daily avg
Humidity
80%
comfortable
UV Index
3
Moderate
Wind
14 km/h
Gusts 30
Crowds
Busy
At attractions
September Sunrise & Sunset
Air Quality
PM2.5
8 μg/m³
PM10
16 μg/m³
Status
good
Feels-Like Temperature & Wind
Feels like
Daytime
16°C
Nighttime
9°C
Humidity and wind affect how the actual temperature feels.
Wind
14 km/h
Max gust 30 km/h
Activities Recommended for September
September Travel Pros & Cons
Pros
- Mild early-autumn weather
- Softening crowds + post-peak prices
- Culture Night (free citywide events)
- Good shoulder-season day trips
Cons
- GAA-final weekends very busy
- Cooling and wetter toward month's end
- Days drawing in
- Changeable weather
September Events & Festivals
- All-Ireland GAA finals (early September, Croke Park) — busy weekends
- Shoulder season — softening crowds and prices
- Culture Night (late September) — free events citywide
- Mellow early autumn
Dublin in September — Full Picture
September is a quietly excellent month — mild early-autumn weather (averaging 17°C/10°C), softening crowds, and the relief of post-peak hotel prices, while days are still reasonably long.
The weather is often pleasant and settled in the first half, gradually turning cooler and wetter toward October. Layers and a waterproof remain the rule, but you'll get plenty of mild, walkable days.
It's a strong shoulder-season choice: lighter crowds at Trinity, the Guinness Storehouse, and on day trips, with better value than summer. The exception is the All-Ireland GAA finals (hurling and football) in early September at Croke Park, which pack the city on those weekends.
Culture Night (late September) is a brilliant free evening when museums, galleries, and historic buildings across Dublin open their doors with special events.
Note: it's the start of the autumn shift, so pack for cooler evenings and more changeable weather than summer. Early September is the safer bet for milder days.
What to Wear & What to Pack
Early autumn — mild and pleasant at around 17°C/10°C, with cooler evenings. Light layers, a sweater or light jacket, and a waterproof. Days still decent (~13h light) but drawing in.
Packing Checklist
Seasonal Weather Overview
Spring (Mar·Apr·May)
12.3°C
5.7°C
11/mo
Summer (Jun·Jul·Aug)
19°C
11.7°C
11/mo
Autumn (Sep·Oct·Nov)
Current13.7°C
7.7°C
12.3/mo
Winter (Dec·Jan·Feb)
8°C
3°C
12.3/mo
Dublin Monthly Weather Comparison
| Month | High | Low | Rain | Sun | Humid | UV | Crowd | Price |
|---|---|---|---|---|---|---|---|---|
| 8° | 3° | 13d·65mm | 1.8h | 85% | 1 | Quiet | Low season | |
| 8° | 3° | 11d·50mm | 2.6h | 84% | 1 | Quiet | Low season | |
| 10° | 4° | 11d·55mm | 3.5h | 81% | 2 | Busy | Peak | |
| 12° | 5° | 11d·55mm | 5.2h | 78% | 3 | Moderate | Shoulder | |
| May (Best) | 15° | 8° | 11d·60mm | 6h | 77% | 4 | Busy | Peak |
| June (Best) | 18° | 11° | 11d·65mm | 6h | 76% | 5 | Very busy | Peak |
| July (Best) | 20° | 12° | 11d·55mm | 5.5h | 76% | 5 | Very busy | Peak |
| August (Best) | 19° | 12° | 11d·70mm | 5h | 78% | 4 | Very busy | Peak |
| 17° | 10° | 11d·65mm | 4.2h | 80% | 3 | Busy | Peak | |
| 14° | 8° | 13d·80mm | 3.2h | 83% | 2 | Moderate | Shoulder | |
| 10° | 5° | 13d·75mm | 2h | 85% | 1 | Quiet | Low season | |
| 8° | 3° | 13d·75mm | 1.6h | 86% | 1 | Busy | Peak |
View Other Months
Dublin September Hotel Picks
Frequently Asked Questions
Is September a good time to visit Dublin?
Dublin in September is high. Tourist crowds are busy and flight/hotel prices are peak.
What's the average temperature in Dublin in September?
Dublin September averages a high of 17°C and a low of 10°C.
Does it rain much in Dublin in September?
Dublin September averages 65mm of rainfall over about 11 rainy days.
What should I wear in Dublin in September?
Early autumn — mild and pleasant at around 17°C/10°C, with cooler evenings. Light layers, a sweater or light jacket, and a waterproof. Days still decent (~13h light) but drawing in.
What time are sunrise and sunset in Dublin in September?
Dublin September sunrise is 07:00 and sunset is 19:35, with 12h 35min of daylight.
What's the air quality like in Dublin in September?
Dublin September air quality (AQI) averages 27, rated Good. PM2.5 averages 8μg/m³.
What activities are recommended in Dublin in September?
In September, Dublin is great for Culture Night free events (late September), Cliffs of Moher & Glendalough day trips, Howth cliff walk.
Is September peak season in Dublin?
Dublin September crowds are busy and prices are peak. Advance reservations are strongly recommended.
Best Months to Visit Dublin
View Other Months
Why you can trust weather guide
Based in Chiang Mai for 8+ years, with 30+ countries visited across Southeast Asia, Japan, and Europe. Every detail in this guide is primary-source verified as of April 2026, with prices auto-refreshed via live exchange rate APIs. This isn't AI-generated boilerplate — it's written from the perspective of someone who has actually been there.