Ireland: where to swim in May?
Ireland, in May: the sea is at 11.5 °C on average along the coast, from 10.8 °C to 12.1 °C depending on the spot. Where the water is warmest (12.1 °C), it is cold. You can swim, but the cold bites quickly: plan a short swim, or wear a wetsuit.
Sea temperature, month by month
| Month | Average temperature | Depending on the spot | Where it is warmest |
|---|---|---|---|
| January | 9.9 °C | 9.2 °C – 10.4 °C | cold |
| February | 9.4 °C | 8.5 °C – 10.2 °C | cold |
| March | 9.4 °C | 8.5 °C – 10.2 °C | cold |
| April | 10.0 °C | 9.2 °C – 10.6 °C | cold |
| May | 11.5 °C | 10.8 °C – 12.1 °C | cold |
| June | 13.6 °C | 12.9 °C – 14.5 °C | cold |
| July | 15.2 °C | 14.2 °C – 16.4 °C | cool |
| August | 15.8 °C | 14.9 °C – 16.5 °C | cool |
| September | 15.0 °C | 14.2 °C – 15.7 °C | cool |
| October | 13.7 °C | 12.9 °C – 14.3 °C | cold |
| November | 12.2 °C | 11.6 °C – 12.8 °C | cold |
| December | 10.8 °C | 10.4 °C – 11.2 °C | cold |
Compared with April, the water warms up by 1.5 °C in May. The warmest month: August (15.8 °C). The coldest: February (9.4 °C).
Nearby, in May
- United Kingdom 9.9 °C · cold
- Netherlands 10.6 °C · cold
- France 14.8 °C · cool
- Denmark 10.1 °C · cold
- Germany 10.6 °C · cold
- Portugal 17.2 °C · cool
And right now?
For the temperature measured right now, station by station and to the hour: Ireland: water temperature
Frequently asked questions
What is the sea temperature in May?
Ireland, in May: 11.5 °C on average along the coast, from 10.8 °C in the coolest waters to 12.1 °C in the warmest (average of the years 2011 to 2025).
Can you swim in May?
Where the water is warmest (12.1 °C), it is cold. You can swim, but the cold bites quickly: plan a short swim, or wear a wetsuit.
What is the best month for swimming?
The water is warmest in August (15.8 °C on average) and coldest in February (9.4 °C). Even where it is warmest, the water never reaches 20 °C in any month; the three warmest months are: August, July, September.
Where is the water warmest in May?
The warmest in May: United Kingdom (9.9 °C), Netherlands (10.6 °C), France (14.8 °C). The coolest: Portugal (17.2 °C).
Where do these temperatures come from?
These are averages of the sea surface temperature from 2011 to 2025, computed from NOAA satellite images (OISST, one value about every 50 km), in a 100 km strip along the coasts of the main country: distant territories (overseas, remote islands) are not counted. It is an estimate, not a measurement taken at the beach: lakes and rivers are not included.