Sea temperature in Ireland
Live water temperatures and swimming conditions across 184 beaches on the Ireland coast.
Best time to swim in Ireland
The sea in Ireland peaks in August, when the water averages around 16°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 9°C, when cold-water swimmers dominate the coast.
Ireland sea temperature history
Long-term climatology for Ireland shows an annual mean sea temperature of 12°C, ranging from 9°C in winter to 16°C at the summer peak.
The seasonal swing is roughly 7°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 Ireland, 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.
Values are area averages; individual beaches vary by exposure and depth.
Ireland sea temperature: frequently asked questions
What is the warmest month to swim in Ireland?
August is the warmest month in Ireland, when the sea averages about 16°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in Ireland?
The coldest month in Ireland is typically February, when the water averages around 9°C. Cold-water swimmers and surfers dominate this period.
When can you swim in Ireland without a wetsuit?
The sea in Ireland 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 Ireland?
Outside peak summer the water in Ireland 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 Ireland?
The long-term annual mean sea temperature in Ireland is about 12°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in Ireland?
The live reading at the top of this page shows the current sea temperature in Ireland, updated hourly from marine buoy and satellite data. The 7-day forecast covers water, air, waves, wind and UV for the week ahead.
Coastal regions of Ireland
Region hubs with live sea temperatures, swim conditions and a beach directory.