Swimming in Ireland in september 2025 Sea temperature by city in september
Do you want to go to the beach in Ireland in september 2025? Is it the right month to go for pleasant temperatures and staying in the water for a long time? The answer is on this page with the sea temperatures in september in Ireland by city and our opinion on the chances of enjoying pleasant sea conditions.
Sea temperature in Ireland in september 2025
Here, find the average sea temperature in Ireland in september in several coastal cities.
Leinster in september
59°F
min: 58°F / max: 60°F
59°F
min: 58°F / max: 60°F
Dalkey Island
59°F
min: 58°F / max: 60°F
Rosslare
60°F
min: 59°F / max: 61°F
60°F
min: 58°F / max: 61°F
Arklow
60°F
min: 59°F / max: 61°F
Munster in september
61°F
min: 58°F / max: 64°F
59°F
min: 57°F / max: 63°F
Ardmore
60°F
min: 58°F / max: 64°F
Castletownbere
61°F
min: 58°F / max: 64°F
59°F
min: 57°F / max: 62°F
Kilkee
59°F
min: 57°F / max: 62°F
Connacht in september
59°F
min: 57°F / max: 61°F
59°F
min: 56°F / max: 62°F
59°F
min: 56°F / max: 62°F
59°F
min: 56°F / max: 61°F
Aran Islands
59°F
min: 56°F / max: 62°F
Ballycastle
58°F
min: 56°F / max: 60°F
North East Ireland (Ulster) in september
58°F
min: 56°F / max: 60°F
58°F
min: 56°F / max: 60°F
58°F
min: 56°F / max: 60°F
Bundoran
58°F
min: 56°F / max: 61°F
Derrybeg
58°F
min: 56°F / max: 60°F
58°F
min: 56°F / max: 60°F
Where should you go swimming in Ireland in the month of september?
Swimming in Ireland in september is cold (in the best case scenario)
In september in Ireland swimming conditions vary by city. Details below:
Swimming in september in Cork, Dingle, Ardmore, Castletownbere, Cliffs of Moher, Kilkee, Rosslare, Shannon, Skellig Islands, Tramore, Valentia, Waterford, Wexford, Arklow, Clonakilty, Cobh, Crosshaven, Dungarvan, Kenmare, Killorglin, Kinsale, Tralee and Youghal is possible... with a wetsuit! Indeed, the water is cold at this time of year with an average temperature of 61°F (min: 58°F/max: 64°F).
Forget about swimming in Dublin, Galway, Belmullet, Connemara National Park, Dundalk, Dungloe, Killybegs, Letterkenny, Achill Island, Aran Islands, Ballycastle, Bundoran, Dalkey Island, Derrybeg, Donegal, Dunfanaghy, Gleann Cholm Cille, Malin Head, Streedagh Point, Balbriggan, Ballina, Ballyshannon, Bray, Buncrana, Dún Laoghaire, Greystones, Laytown, Malahide, Moville, Skerries, Sligo, Westport and Wicklow in september! The water temperature is freezing, reaching as low as 58°F (and only 60°F at the best of times). Our advice: plan on sightseeing, and don't bring your beach towel!
Where to go swimming in Ireland in september: the map of sea temperatures
ideal swimming 
pleasant swimming 
cool swimming 
cold swimming 
freezing swimmingWater temperature and seasonal norms in september
Dublin
| September | |||
| Average sea temperature | 59°F | ||
| Minimum sea temperature | 58°F | ||
| Maximum sea temperature | 60°F | ||
| Average outside temperature | 58°F | ||
| Maximum outside temperature | 61°F | ||
| Minimum outside temperature | 54°F | ||
| Precipitation | 2.7in | ||
| Number of days of precipitation | 4 jour(s) (13%) | ||
| Cloud cover | 50% | ||
| Our opinion | freezing swimming |
More information on swimming in Dublin in september
Cork
| September | |||
| Average sea temperature | 61°F | ||
| Minimum sea temperature | 58°F | ||
| Maximum sea temperature | 64°F | ||
| Average outside temperature | 58°F | ||
| Maximum outside temperature | 63°F | ||
| Minimum outside temperature | 54°F | ||
| Precipitation | 3.9in | ||
| Number of days of precipitation | 5 jour(s) (17%) | ||
| Cloud cover | 52% | ||
| Our opinion | cold swimming |
More information on swimming in Cork in september
Galway
| September | |||
| Average sea temperature | 59°F | ||
| Minimum sea temperature | 57°F | ||
| Maximum sea temperature | 61°F | ||
| Average outside temperature | 58°F | ||
| Maximum outside temperature | 63°F | ||
| Minimum outside temperature | 52°F | ||
| Precipitation | 4.2in | ||
| Number of days of precipitation | 6 jour(s) (20%) | ||
| Cloud cover | 61% | ||
| Our opinion | freezing swimming |
More information on swimming in Galway in september
Belmullet
| September | |||
| Average sea temperature | 59°F | ||
| Minimum sea temperature | 56°F | ||
| Maximum sea temperature | 62°F | ||
| Average outside temperature | 59°F | ||
| Maximum outside temperature | 59°F | ||
| Minimum outside temperature | 58°F | ||
| Precipitation | 6.6in | ||
| Number of days of precipitation | 11 jour(s) (36%) | ||
| Cloud cover | 61% | ||
| Our opinion | freezing swimming |
More information on swimming in Belmullet in september
Connemara National Park
| September | |||
| Average sea temperature | 59°F | ||
| Minimum sea temperature | 56°F | ||
| Maximum sea temperature | 62°F | ||
| Average outside temperature | 56°F | ||
| Maximum outside temperature | 59°F | ||
| Minimum outside temperature | 52°F | ||
| Precipitation | 3.7in | ||
| Number of days of precipitation | 6 jour(s) (20%) | ||
| Cloud cover | 62% | ||
| Our opinion | freezing swimming |
More information on swimming in Connemara National Park in september
List of coastal cities in Ireland
| Dublin in september | freezing swimming |
| Cork in september | cold swimming |
| Galway in september | freezing swimming |
| Belmullet in september | freezing swimming |
| Connemara National Park in september | freezing swimming |
| Dingle in september | cold swimming |
| Dundalk in september | freezing swimming |
| Dungloe in september | freezing swimming |
| Killybegs in september | freezing swimming |
| Letterkenny in september | freezing swimming |
| Achill Island in september | freezing swimming |
| Aran Islands in september | freezing swimming |
| Ardmore in september | cold swimming |
| Ballycastle in september | freezing swimming |
| Bundoran in september | freezing swimming |
| Castletownbere in september | cold swimming |
| Dalkey Island in september | freezing swimming |
| Derrybeg in september | freezing swimming |
| Donegal in september | freezing swimming |
| Dunfanaghy in september | freezing swimming |
| Cliffs of Moher in september | cold swimming |
| Gleann Cholm Cille in september | freezing swimming |
| Kilkee in september | cold swimming |
| Malin Head in september | freezing swimming |
| Rosslare in september | cold swimming |
| Shannon in september | cold swimming |
| Skellig Islands in september | cold swimming |
| Streedagh Point in september | freezing swimming |
| Tramore in september | cold swimming |
| Valentia in september | cold swimming |
| Waterford in september | cold swimming |
| Wexford in september | cold swimming |
| Arklow in september | cold swimming |
| Balbriggan in september | freezing swimming |
| Ballina in september | freezing swimming |
| Ballyshannon in september | freezing swimming |
| Bray in september | freezing swimming |
| Buncrana in september | freezing swimming |
| Clonakilty in september | cold swimming |
| Cobh in september | cold swimming |
| Crosshaven in september | cold swimming |
| Dún Laoghaire in september | freezing swimming |
| Dungarvan in september | cold swimming |
| Greystones in september | freezing swimming |
| Kenmare in september | cold swimming |
| Killorglin in september | cold swimming |
| Kinsale in september | cold swimming |
| Laytown in september | freezing swimming |
| Malahide in september | freezing swimming |
| Moville in september | freezing swimming |
| Skerries in september | freezing swimming |
| Sligo in september | freezing swimming |
| Tralee in september | cold swimming |
| Westport in september | freezing swimming |
| Wicklow in september | freezing swimming |
| Youghal in september | cold swimming |