Swimming in Wales in september 2025 Sea temperature by city in september
Do you want to go to the beach in Wales 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 Wales by city and our opinion on the chances of enjoying pleasant sea conditions.
Sea temperature in Wales in september 2025
Here, find the average sea temperature in Wales in september in several coastal cities.
62°F
min: 61°F / max: 64°F
Conwy
61°F
min: 60°F / max: 63°F
Holyhead
59°F
min: 58°F / max: 61°F
61°F
min: 60°F / max: 63°F
Snowdonia National Park
60°F
min: 59°F / max: 62°F
62°F
min: 61°F / max: 64°F
Aberystwyth
61°F
min: 59°F / max: 62°F
Amlwch
61°F
min: 59°F / max: 61°F
61°F
min: 59°F / max: 62°F
Barry
63°F
min: 61°F / max: 64°F
Buckley
62°F
min: 60°F / max: 63°F
Fishguard
61°F
min: 60°F / max: 63°F
61°F
min: 60°F / max: 63°F
Llanelli
62°F
min: 61°F / max: 64°F
Porthcawl
63°F
min: 61°F / max: 64°F
Where should you go swimming in Wales in the month of september?
Swimming in Wales in september is cold
In september in Wales swimming conditions are generally the same everywhere.
Swimming in september in Cardiff, Conwy, Holyhead, Pembrokeshire, Snowdonia National Park, Swansea, Aberystwyth, Amlwch, Barmouth, Barry, Buckley, Fishguard, Llandudno, Llanelli and Porthcawl is possible... with a wetsuit! Indeed, the water is cold at this time of year with an average temperature of 62°F (min: 61°F/max: 64°F).
Where to go swimming in Wales in september: the map of sea temperatures
ideal swimming 
pleasant swimming 
cool swimming 
cold swimming 
freezing swimmingWater temperature and seasonal norms in september
Cardiff
| September | |||
| Average sea temperature | 62°F | ||
| Minimum sea temperature | 61°F | ||
| Maximum sea temperature | 64°F | ||
| Average outside temperature | 59°F | ||
| Maximum outside temperature | 65°F | ||
| Minimum outside temperature | 54°F | ||
| Precipitation | 1.8in | ||
| Number of days of precipitation | 3 jour(s) (9%) | ||
| Cloud cover | 48% | ||
| Our opinion | cold swimming |
More information on swimming in Cardiff in september
Conwy
| September | |||
| Average sea temperature | 61°F | ||
| Minimum sea temperature | 60°F | ||
| Maximum sea temperature | 63°F | ||
| Average outside temperature | 58°F | ||
| Maximum outside temperature | 61°F | ||
| Minimum outside temperature | 54°F | ||
| Precipitation | 4.4in | ||
| Number of days of precipitation | 8 jour(s) (25%) | ||
| Cloud cover | 53% | ||
| Our opinion | cold swimming |
Holyhead
| September | |||
| Average sea temperature | 59°F | ||
| Minimum sea temperature | 58°F | ||
| Maximum sea temperature | 61°F | ||
| Average outside temperature | 59°F | ||
| Maximum outside temperature | 61°F | ||
| Minimum outside temperature | 58°F | ||
| Precipitation | 5.6in | ||
| Number of days of precipitation | 9 jour(s) (29%) | ||
| Cloud cover | 52% | ||
| Our opinion | cold swimming |
Pembrokeshire
| September | |||
| Average sea temperature | 61°F | ||
| Minimum sea temperature | 60°F | ||
| Maximum sea temperature | 63°F | ||
| Average outside temperature | 61°F | ||
| Maximum outside temperature | 63°F | ||
| Minimum outside temperature | 59°F | ||
| Precipitation | 4.8in | ||
| Number of days of precipitation | 8 jour(s) (25%) | ||
| Cloud cover | 48% | ||
| Our opinion | cold swimming |
More information on swimming in Pembrokeshire in september
Snowdonia National Park
| September | |||
| Average sea temperature | 60°F | ||
| Minimum sea temperature | 59°F | ||
| Maximum sea temperature | 62°F | ||
| Average outside temperature | 54°F | ||
| Maximum outside temperature | 58°F | ||
| Minimum outside temperature | 49°F | ||
| Precipitation | 5in | ||
| Number of days of precipitation | 7 jour(s) (24%) | ||
| Cloud cover | 60% | ||
| Our opinion | cold swimming |
List of coastal cities in Wales
| Cardiff in september | cold swimming |
| Conwy in september | cold swimming |
| Holyhead in september | cold swimming |
| Pembrokeshire in september | cold swimming |
| Snowdonia National Park in september | cold swimming |
| Swansea in september | cold swimming |
| Aberystwyth in september | cold swimming |
| Amlwch in september | cold swimming |
| Barmouth in september | cold swimming |
| Barry in september | cold swimming |
| Buckley in september | cold swimming |
| Fishguard in september | cold swimming |
| Llandudno in september | cold swimming |
| Llanelli in september | cold swimming |
| Porthcawl in september | cold swimming |