Dun Laoghaire Weather in September

September in Dun Laoghaire brings moderate temperatures, with daytime highs of 17°C (63°F) and nights around 11°C (52°F). Quite a bit of rainfall is expected, around 80 mm (3.1 in), so pack an umbrella.

Rainfall in Dun Laoghaire in September

On average, there are about 15 days with rain during this month, averaging 80 mm (3.1 in). Rain this month is fairly typical, a standard mix of wet and dry days with no particularly heavy or persistent showers.

Temperature in Dun Laoghaire in September

Expect highs of 17°C (63°F) in Dun Laoghaire in September, with nights dropping to around 11°C (52°F). September marks the summer season. The difference between afternoon and evening temperatures is usually noticeable. Nights cool down to 11°C (52°F), so a light jacket or extra layer is useful once the sun goes down. On the plus side, the cooler nights make for comfortable sleeping conditions.

Sunshine in Dun Laoghaire in September

With about 128 hours of sunshine, the area enjoys a nice balance of sun and overcast, creating a pleasant environment.

Wind Speed in Dun Laoghaire in September

September sees wind speeds averaging 4 m/s (8 knots). You'll experience variable conditions with moderate winds that create small waves on water and keep branches moving. Conditions range from light winds to moderate breezes throughout the month.

Average water temperature in September

With water at 15°C (59°F), it's on the cooler side. Keen swimmers won't be put off, but those who prefer warm water may find it less enjoyable.

For Dun Laoghaire itself, July and August generally stand out with the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.

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For a detailed overview over the year and the best time to visit Ireland, check out our Dun Laoghaire's climate page.

Dun Laoghaire Temperature in September

Min Temperature 11°C (52°F)  

Max Temperature 17°C (63°F)  

Water Temperature 15°C (59°F) *  

Chance of Rain 50%  

Precipitation 80 mm (3.1 in)  

Rainy days 15 days  

Humidity 71% *  

Windspeed 4 m/s (8 knots) *  

Sunshine 128 hours *  

Percentage Sunshine 33% *  

* Data from: Dublin, Ireland (17 KM, 10 Miles).

What to Wear in Dun Laoghaire in September

Pleasant temperatures in September mean you can pack light but flexibel pieces. Think cotton t-shirts, comfortable walking shorts, and one warmer layer for evenings. A light sweater or denim jacket works well. Prepare for significant rainfall with proper waterproof clothing and shoes. The water temperature sits at about 15°C (59°F), which is too chilly for most people to enjoy swimming. Leave the swimsuit at home unless you love cold water. Bring sunglasses since you'll have some sunny periods throughout the month

What To Do in Dun Laoghaire in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

6/10

Cycling

6/10

Walking

6/10

Camping

8/10

Outdoor sports

9/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit Ireland, check out our Dun Laoghaire's climate page.

More climate data for Dun Laoghaire

Temperature Rainfall Sunshine Humidity Wind Speed Water Temp

See the full Dun Laoghaire climate overview or explore weather in Ireland.