Weather in Dublin 🇮🇪
Monthly weather averages & travel planning
September
Avg Temp
17°C
Rain Days
12 days
Sun Hours
8 hrs
Humidity
65%
Europe › 🇮🇪 Ireland › Dublin
Updated: March 2026
Is September a Good Time to Visit Dublin?
5/10
Fair
September is a fair time to visit Dublin (5/10). With 8 daily sunshine hours and only 12 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 7th sunniest of the year in Dublin. Culture-focused travellers and those who prefer lighter crowds will find September a practical choice, with prices running lower than peak May without sacrificing all the good weather. October offers a similar profile at lower hotel rates if dates are flexible. The main practical note: Dublin's popular sites are busiest between 10am and 3pm regardless of season. Arriving at opening time or after 4pm makes a significant difference to the experience. Planning tips: accommodation is generally available without long lead times, and flight prices are typically lower than peak season. Flexible travellers will find the best deals by booking 2-4 weeks ahead. Mid-week arrivals consistently unlock lower hotel rates than weekend check-ins.
vs August:19°C avg high
September sits at a particular moment in Dublin's seasonal arc. Temperatures average 17°C during the day, placing this month in a comfortable middle band, noticeably warmer than the depths of winter but without midsummer extremes. Against the seasonal backdrop, 12 rainy days and 8 sunshine hours per day help calibrate expectations for what actually awaits on the ground.
17°C
63°F
Avg High
11°C
52°F
Avg Low
12 days
70 mm total
Rain Days
8h
per day avg
Sunshine
65%
Moderate
Humidity
Temperature in Dublin in September
The 6°C day-night temperature range is typical for continental climates: a light jacket in the morning that you shed by midday and need again after sunset. Humidity averages 65%, which is comfortable for most visitors. On warmer days, lighter fabrics help with the mild stickiness in the afternoon. UV index averages 6 this month, classed as moderate. Sunscreen is a sensible precaution for extended outdoor time, particularly at midday. Wind averages 21 km/h, light enough to be refreshing on warm days but noticeable in open coastal areas or elevated viewpoints. In Fahrenheit: 63°F average high, 52°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Temperature Trends
High
Low
Rainfall (mm)
0-20 mm21-50 mm51-100 mm100+ mm
What to Wear in Dublin in September
Morning11°CBefore the day warms up
Afternoon17°CPeak daytime temperature
Evening14°CAfter sunset cools down
Packing for Dublin in September means dressing for 17°C days and 11°C evenings. A mid-weight jacket over a sweater handles 17°C daytime temperatures; the combination stays comfortable all day without overheating. Evening temperatures settle at 11°C, a modest 6°C drop that a light cardigan or denim jacket covers. European cobblestones reward low-profile walking shoes over flip-flops or heels, with cushioned trainers or leather walking shoes being the practical choice. A compact foldable umbrella weighs almost nothing and earns its keep across 12 potential rainy days.
Local tip: Dublin's cobbled streets turn slippery in the rain. Waterproof walking shoes with a non-slip sole outperform fashionable footwear on wet stone, and you'll cover significantly more ground in comfort.
Events in Dublin in September
September has no major festivals or public holidays in Dublin, which is one of its practical advantages for independent travellers. Attractions run at lower capacity than during peak event periods, queues are shorter, and accommodation is easier to find without needing to book many months in advance. Local restaurants, markets, and transport operate at a relaxed pace, making this an ideal time for visitors who prefer a more authentic, unhurried experience of everyday city life rather than large crowds drawn in by a single major headline event.
What to Pack for Dublin in September
Based on 17°C average highs and 12 rainy days
- Light jacket or cardigan for cooler evenings
- Mix of short and long-sleeve layers
- Comfortable walking shoes with good arch support
- Compact folding umbrella
- Waterproof outer layer or packable rain jacket
- Quick-dry clothing that recovers fast after a shower
- Universal travel adapter
- Small day pack for city exploration
- Reusable water bottle
Best Activities in Dublin in September
- Explore the old town's cobblestone backstreetsMorning (9-11am)At 17°C, conditions are pleasant for unhurried exploration on foot
- Visit hilltop viewpoints for panoramic city viewsLate afternoon (4-6pm)Low sun angle creates dramatic light for photography while temperatures remain comfortable
- Bicycle rental for a half-day city circuitMid-morning startMild 17°C temperatures are ideal for extended cycling without excessive effort
- Boat tour of the river, bay, or canal networkLate morning departureComfortable weather makes open-deck boats viable without wind-chill concerns
- Afternoon in a world-class museum or galleryAfternoon (2-5pm)Pairs well with outdoor morning activities and provides a mid-day rest from sightseeing
- Coffee-house or traditional cafe culture experienceMid-morning or post-lunchA cultural ritual in this region that rewards slow appreciation regardless of weather
- Evening live music, theatre, or opera performanceEvening shows typically at 7-9pmConsistent evening temperatures make getting to and from evening venues comfortable
- Visit the main botanical garden or city park at seasonal peakYear-round; best light in morningSeptember brings distinct seasonal changes to public green spaces worth exploring
- Try the seasonal farmer's market for local produce and street foodSaturday morning markets typically 8am-1pmSeptember seasonal produce is at peak availability, offering dishes not found at other times of year
Why is Dublin mild in September?
September brings the first meaningful shift toward cooler conditions in Dublin, as the sun angle drops and day length shortens. Temperatures averaging 17°C by day and 11°C overnight are still comfortable by most standards, but the trend is clearly downward. At 53 degrees north latitude, autumn light has a particular quality: lower in the sky and warmer in tone, it gives the city a photogenic quality quite different from summer. Evening temperatures already demand a jacket, but midday hours stay pleasant for sightseeing. Climate data: Open-Meteo ERA5 (1991–2020).
Sunshine Hours
The average number of hours per day with direct sunlight. Calculated from satellite measurements. Days with more than 7 hours of sunshine are ideal for outdoor activities. Under 3 hours means overcast conditions dominate.
UV Index
A scale from 0-11+ measuring ultraviolet radiation intensity. UV 0-2: Minimal risk. UV 3-5: Moderate, wear sunscreen. UV 6-7: High, hat and SPF 30+ essential. UV 8-10: Very High, limit midday exposure. UV 11+: Extreme, seek shade between 10am-4pm.
Rain Days
A rain day is counted when precipitation exceeds 0.1mm. This threshold captures even light drizzle. Unlike total rainfall in mm, rain days tells you how often you might need an umbrella, which is useful for planning outdoor activities.
Humidity
Relative humidity as a percentage. Below 40%: Dry, skin and throat may feel parched. 40-60%: Comfortable, ideal for most people. 60-80%: Sticky, light breathable fabrics recommended. Above 80%: Muggy, heat feels more intense; quick-dry clothing is essential.
Frequently Asked Questions
Dublin in September
In September, Dublin experiences average highs of 17°C (63°F) and lows of 11°C (52°F). Expect around 12 rainy days and 8 hours of sunshine per day, with humidity averaging 65%. The 6°C gap between daytime and overnight temperatures is worth planning around: light layers work for most visitors during the day, but an overshirt or cardigan handles the cooler evenings. UV index averages 6, so sun protection is advisable on clear days.
Dublin typically sees 12 rainy days in September, with total precipitation of around 70mm. Rain is moderate and manageable. Showers tend to pass quickly, and a light rain layer or foldable umbrella is sufficient protection for most days. For context, the driest month in Dublin typically sees 4-6 fewer rain days than September.
Pack a warm jacket, sweaters, and layering pieces for Dublin in September. Temperatures can drop to 11°C at night, so thermal underlayers are advisable for evening outings. Waterproof footwear is important with 12 rainy days expected. A scarf, hat, and gloves handle the windchill on clear cold days, which often feel colder than the thermometer reads.
September is a reasonable time to visit Dublin. Expect 12 rainy days, so pack a light rain layer for flexibility. Average temperatures of 17°C make outdoor exploration comfortable during the dry periods. With 8 daily sunshine hours, there are reliable windows of good weather to plan outdoor activities around, even if the month is not the driest on the calendar.
The average high temperature in Dublin in September is 17°C (63°F), and the average low is 11°C (52°F). The mean daily temperature is approximately 14°C (57°F). The day-to-night range of 6°C is moderate, meaning a single light jacket covers most situations. These are 30-year climate normals based on the 1991 to 2020 reference period; individual years will vary, particularly in transitional months like spring and autumn.
The best month to visit Dublin is generally May. May offers the most sunshine at 11 hours per day. Average temperatures reach 15°C, making it comfortable for sightseeing, outdoor dining, and exploring the city. If your travel dates are flexible, planning your trip around May gives you the best chance of dry, bright weather.
September is shoulder or low season in Dublin, meaning fewer tourists and generally lower prices than peak months. With 8 sunshine hours and 12 rainy days, the weather is less of a draw for mass tourism. This is an advantage for travellers who prefer a quieter, more relaxed experience with shorter queues and easier accommodation availability.
In September, Dublin suits a range of activities thanks to cool conditions around 17°C. Mix of indoor and outdoor activities works well given the moderate chance of rain. Top options include exploring historic neighbourhoods, visiting museums and galleries, local food markets, and day trips to surrounding areas. With 8 hours of sunshine, parks and waterfront walks are particularly enjoyable.
September ranks 7th sunniest of the year in Dublin, with an average 8 daily sunshine hours. The driest months are February, March, and September. July is the hottest month (19°C avg high); January is the coolest (8°C). From here, temperatures fall 4°C into October. Compared to last month (August: 19°C high, 14 rain days), September is cooler and drier. September sits in the middle of the annual sunshine ranking for Dublin, offering a reasonable balance of good weather and manageable crowds.
Year-Round Climate
| Month | High | Low | Rain Days | Sun | Details |
|---|---|---|---|---|---|
| January | 8°C | 4°C | 13 | 4h | View |
| February | 8°C | 3°C | 12 | 6h | View |
| March | 10°C | 4°C | 12 | 8h | View |
| April | 12°C | 6°C | 14 | 10h | View |
| May | 15°C | 8°C | 14 | 11h | View |
| June | 17°C | 11°C | 13 | 11h | View |
| July | 19°C | 13°C | 15 | 10h | View |
| August | 19°C | 13°C | 14 | 10h | View |
| September | 17°C | 11°C | 12 | 8h | View |
| October | 13°C | 9°C | 12 | 6h | View |
| November | 10°C | 6°C | 13 | 5h | View |
| December | 8°C | 4°C | 13 | 4h | View |
January
13 rain days, 4h sun
8°4°
February
12 rain days, 6h sun
8°3°
March
12 rain days, 8h sun
10°4°
April
14 rain days, 10h sun
12°6°
May
14 rain days, 11h sun
15°8°
June
13 rain days, 11h sun
17°11°
July
15 rain days, 10h sun
19°13°
August
14 rain days, 10h sun
19°13°
September
12 rain days, 8h sun
17°11°
October
12 rain days, 6h sun
13°9°
November
13 rain days, 5h sun
10°6°
December
13 rain days, 4h sun
8°4°
Other Months in Dublin
Plan Your Trip to Dublin
Nearby Destinations
Cities within 500 km with comparable weather conditions
Data Sources for Dublin
Climate normals represent 30-year averages (1991-2020). Individual years may vary.