North Wales is a coastal area of United Kingdom on the Irish Sea, with 21 tracked beaches. The sea here ranges from about 8°C in the coolest month to 17°C at the summer peak, with roughly 0 months a year sitting above 20°C — the level most swimmers describe as pleasant without a wetsuit. Use the beach list below to check the current sea temperature at each spot before you head out.
North Wales
21 tracked beaches in North Wales, United Kingdom, with live Irish Sea temperatures.
Sea
Irish Sea
Avg sea temp now
16.2°C
Best months
Warmest August
Best time to swim in North Wales
The sea in North Wales peaks in August, when the water averages around 17°C.
On average, 0 months a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.
Outside peak season the water drops toward 9°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable.
The coldest month is typically February at around 8°C, when cold-water swimmers dominate the coast.
North Wales sea temperature history
Long-term climatology for North Wales shows an annual mean sea temperature of 12°C, ranging from 8°C in winter to 17°C at the summer peak.
The seasonal swing is roughly 9°C between the coldest and warmest month — a useful yardstick when comparing years or checking whether the current sea is running above or below average.
Recent decades have trended slightly warmer at North Wales, in line with regional sea-surface temperature records for the wider basin.
Monthly averages below are drawn from multi-decadal climatology and are updated as new observations arrive.
Jan
9°C
Feb
8°C
Mar
8°C
Apr
9°C
May
11°C
Jun
14°C
Jul
16°C
Aug
17°C
Sep
16°C
Oct
14°C
Nov
12°C
Dec
10°C
Values are area averages; individual beaches vary by exposure and depth.
North Wales sea temperature: frequently asked questions
What is the warmest month to swim in North Wales?
August is the warmest month in North Wales, when the sea averages about 17°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in North Wales?
The coldest month in North Wales is typically February, when the water averages around 8°C. Cold-water swimmers and surfers dominate this period.
When can you swim in North Wales without a wetsuit?
The sea in North Wales rarely climbs above 20°C, so a wetsuit is recommended year-round for anything longer than a quick dip.
Do I need a wetsuit in North Wales?
Outside peak summer the water in North Wales drops toward 9°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable. In peak months most swimmers go without.
What is the average sea temperature in North Wales?
The long-term annual mean sea temperature in North Wales is about 12°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in North Wales?
The live reading at the top of this page shows the current sea temperature in North Wales, updated hourly from marine buoy and satellite data. The 7-day forecast covers water, air, waves, wind and UV for the week ahead.
Beaches in the North Wales
Ranked by current live sea temperature.
- 1Abersoch BeachAbersoch, United Kingdom16.7°C
- 2Nefyn BeachNefyn, United Kingdom16.7°C
- 3Llandudno West ShoreLlandudno, United Kingdom16.7°C
- 4Dinas DinlleCaernarfon, United Kingdom16.6°C
- 5Aberdovey BeachAberdovey, United Kingdom16.4°C
- 6Colwyn BayColwyn Bay, United Kingdom16.4°C
- 7Tywyn BeachTywyn, United Kingdom16.3°C
- 8Aberdaron BeachAberdaron, United Kingdom16.3°C
- 9Rhosneigr BeachRhosneigr, United Kingdom16.3°C
- 10Benllech BeachBenllech, United Kingdom16.3°C
- 11Prestatyn BeachPrestatyn, United Kingdom16.3°C
- 12Porth NeigwlLlanengan, United Kingdom16.2°C
- 13Rhos-on-SeaColwyn Bay, United Kingdom16.2°C
- 14Barmouth BeachBarmouth, United Kingdom16.1°C
- 15Red Wharf BayPentraeth, United Kingdom16.1°C
- 16Rhyl BeachRhyl, United Kingdom16.1°C
- 17Harlech BeachHarlech, United Kingdom16.0°C
- 18PorthdinllaenMorfa Nefyn, United Kingdom15.7°C
- 19Black Rock SandsPorthmadog, United Kingdom15.6°C
- 20Trearddur BayTrearddur, United Kingdom15.6°C
- 21Llandudno North ShoreLlandudno, United Kingdom15.6°C
Swimming in the North Wales — FAQ
How warm is the sea in the North Wales in September?
The Irish Sea off the North Wales averages about 16.0°C in September, based on long-term monthly averages for this coast.
When is the best time to swim in the North Wales?
The North Wales is warmest in August (around 17.0°C) and coldest in February (around 8.0°C). There are typically 0 months a year when the water sits above 22°C.
What is the average yearly sea temperature in the North Wales?
Across all twelve months, the sea in the North Wales averages about 12.0°C.
Do you need a wetsuit to swim in the North Wales?
The sea in the North Wales stays below 22°C even at its warmest (~17.0°C in August), so a 3/2mm or thicker wetsuit is recommended for longer swims year-round.