Swimming in Northern Ireland in august 2025 Sea temperature by city in august
Do you want to go to the beach in Northern Ireland in august 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 august in Northern Ireland by city and our opinion on the chances of enjoying pleasant sea conditions.
Sea temperature in Northern Ireland in august 2025
Here, find the average sea temperature in Northern Ireland in august in several coastal cities.
County Antrim in august
58°F
min: 57°F / max: 59°F
Ballycastle (Causeway Coast)
58°F
min: 56°F / max: 59°F
Larne
58°F
min: 57°F / max: 60°F
Carrickfergus
58°F
min: 56°F / max: 60°F
Glenariff
58°F
min: 56°F / max: 59°F
Newtownabbey
58°F
min: 57°F / max: 59°F
County Londonderry in august
59°F
min: 57°F / max: 61°F
Castlerock
58°F
min: 56°F / max: 60°F
Limavady
58°F
min: 56°F / max: 60°F
58°F
min: 56°F / max: 60°F
County Down in august
Donwpatrick
59°F
min: 57°F / max: 60°F
Annalong
59°F
min: 57°F / max: 60°F
Ballywalter
58°F
min: 56°F / max: 60°F
Bangor
58°F
min: 56°F / max: 59°F
Donaghadee
58°F
min: 57°F / max: 60°F
Dundrum
59°F
min: 57°F / max: 61°F
Where should you go swimming in Northern Ireland in the month of august?
Swimming in Northern Ireland in august is freezing
In august in Northern Ireland swimming conditions are generally the same everywhere.
Forget about swimming in Belfast, Ballycastle (Causeway Coast), Derry (Londonderry), Donwpatrick, Larne, Annalong, Ballywalter, Bangor, Carrickfergus, Castlerock, Donaghadee, Dundrum, Glenariff, Holywood, Kilkeel, Limavady, Millisle, Newcastle, Newtownabbey, Newtownards, Portrush, Portstewart and Warrenpoint in august! The water temperature is freezing, reaching as low as 57°F (and only 59°F at the best of times). Our advice: plan on sightseeing, and don't bring your beach towel!
Where to go swimming in Northern Ireland in august: the map of sea temperatures
ideal swimming 
pleasant swimming 
cool swimming 
cold swimming 
freezing swimmingWater temperature and seasonal norms in august
Belfast
| August | |||
| Average sea temperature | 58°F | ||
| Minimum sea temperature | 57°F | ||
| Maximum sea temperature | 59°F | ||
| Average outside temperature | 59°F | ||
| Maximum outside temperature | 65°F | ||
| Minimum outside temperature | 56°F | ||
| Precipitation | 5.9in | ||
| Number of days of precipitation | 10 jour(s) (32%) | ||
| Cloud cover | 59% | ||
| Our opinion | freezing swimming |
More information on swimming in Belfast in august
Ballycastle (Causeway Coast)
| August | |||
| Average sea temperature | 58°F | ||
| Minimum sea temperature | 56°F | ||
| Maximum sea temperature | 59°F | ||
| Average outside temperature | 59°F | ||
| Maximum outside temperature | 61°F | ||
| Minimum outside temperature | 56°F | ||
| Precipitation | 7.4in | ||
| Number of days of precipitation | 13 jour(s) (41%) | ||
| Cloud cover | 57% | ||
| Our opinion | freezing swimming |
Derry (Londonderry)
| August | |||
| 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 | 54°F | ||
| Precipitation | 2.6in | ||
| Number of days of precipitation | 3 jour(s) (9%) | ||
| Cloud cover | 69% | ||
| Our opinion | freezing swimming |
More information on swimming in Derry (Londonderry) in august
Donwpatrick
| August | |||
| Average sea temperature | 59°F | ||
| Minimum sea temperature | 57°F | ||
| Maximum sea temperature | 60°F | ||
| Average outside temperature | 59°F | ||
| Maximum outside temperature | 63°F | ||
| Minimum outside temperature | 58°F | ||
| Precipitation | 3.9in | ||
| Number of days of precipitation | 6 jour(s) (19%) | ||
| Cloud cover | 52% | ||
| Our opinion | freezing swimming |
Larne
| August | |||
| Average sea temperature | 58°F | ||
| Minimum sea temperature | 57°F | ||
| Maximum sea temperature | 60°F | ||
| Average outside temperature | 59°F | ||
| Maximum outside temperature | 63°F | ||
| Minimum outside temperature | 56°F | ||
| Precipitation | 6.3in | ||
| Number of days of precipitation | 10 jour(s) (34%) | ||
| Cloud cover | 56% | ||
| Our opinion | freezing swimming |
List of coastal cities in Northern Ireland
| Belfast in august | freezing swimming |
| Ballycastle (Causeway Coast) in august | freezing swimming |
| Derry (Londonderry) in august | freezing swimming |
| Donwpatrick in august | freezing swimming |
| Larne in august | freezing swimming |
| Annalong in august | freezing swimming |
| Ballywalter in august | freezing swimming |
| Bangor in august | freezing swimming |
| Carrickfergus in august | freezing swimming |
| Castlerock in august | freezing swimming |
| Donaghadee in august | freezing swimming |
| Dundrum in august | freezing swimming |
| Glenariff in august | freezing swimming |
| Holywood in august | freezing swimming |
| Kilkeel in august | freezing swimming |
| Limavady in august | freezing swimming |
| Millisle in august | freezing swimming |
| Newcastle in august | freezing swimming |
| Newtownabbey in august | freezing swimming |
| Newtownards in august | freezing swimming |
| Portrush in august | freezing swimming |
| Portstewart in august | freezing swimming |
| Warrenpoint in august | freezing swimming |