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Celtic Sea

Celtic Sea Water Temperature: Current & Historical Data for Coastal Resorts

We find every spot where you can swim and tell you what the water temperature is there today and throughout the year

Current water temperature

42°F

minimal

46°F

average

50°F

maximum

Graph of Water Temperature Changes in the Celtic Sea Over the Last 60 Days

Water temperature in the Celtic Sea by month

Month	Minimum	Maximum
January	39°F	55°F
February	39°F	54°F
March	41°F	54°F
April	43°F	57°F
May	46°F	61°F
June	48°F	66°F
July	52°F	70°F
August	55°F	70°F
September	55°F	70°F
October	52°F	66°F
November	48°F	63°F
December	43°F	59°F

What is known about the Celtic Sea?

The Celtic Sea, located to the south of Ireland and west of Cornwall, experiences cool water temperatures throughout the year due to its exposure to the North Atlantic. During the summer months, from June to September, sea temperatures typically range from 57–63°F (14–17°C), with the warmest waters found in late August. The coasts of southern Ireland, including Cork and Waterford, as well as southwestern England, such as Cornwall, offer the best conditions for swimming, though the water remains relatively cold compared to more southerly seas. Despite the chilly temperatures, summer attracts swimmers, surfers, and other water sports enthusiasts, particularly in more sheltered bays.

In winter, from December to March, the Celtic Sea becomes significantly colder, with temperatures dropping to 48–54°F (9–12°C). These conditions make swimming without a wetsuit challenging, and most people prefer cold-water dips rather than extended swims. The sea is also known for strong waves and changing currents, making it a popular destination for surfers, especially along the coasts of Ireland and Cornwall. While summer provides the best opportunities for swimming, the Celtic Sea is better suited for water sports and cold-water swimming outside of the warmest months.

List of Countries Bordering the Celtic Sea

Popular Resorts of the Celtic Sea with the Warmest Water Today

50°F

Locquirec

France

50°F

Perros-Guirec

France

50°F

Locquémeau

France

50°F

Roscoff

France

50°F

Sibiril

France

50°F

Santec

France

Popular Resorts on the Celtic Sea Coast

Nearest Seas and Oceans

Frequently Asked Questions About the Celtic Sea

What is the water temperature in the Celtic Sea right now?

The water temperature in the Celtic Sea today ranges from 43°F (6°C) in Arnside (United Kingdom) to 50°F (10°C) in Locquirec (France).

Is it possible to swim in the Celtic Sea?

Yes, it is possible to swim in the Celtic Sea, although the water is cooler compared to warmer regions, especially during the winter months.

In which month does the Celtic Sea have the highest and lowest water temperatures?

The highest water temperature in the Celtic Sea occurs in July, reaching 70°F (21°C), while the lowest is in January, dropping to 39°F (4°C).

Is the Celtic Sea colder than the Bay of Biscay?

Yes, the Celtic Sea is slightly colder than the Bay of Biscay, as its average annual water temperature is 54°F (12°C), while the Bay of Biscay's is 59°F (15°C).

Which countries are washed by the Celtic Sea?

The Celtic Sea washes United Kingdom, Ireland, and France.

What are the most popular resorts located on the Celtic Sea?

The most popular beach destinations on the Celtic Sea are Saint-Malo (France), Brest (France), Binic (France), Le Minihic-sur-Rance (France), Penarth (United Kingdom), Cancale (France), Saint-Briac-sur-Mer (France), Cork (Ireland), Dunmore East (Ireland), Newquay (United Kingdom).

Do you have any extended or additional information about the Celtic Sea?

The Celtic Sea is the sea of the Atlantic Ocean basin. Washes part of Ireland, Great Britain and France. The sea borders are limited by the St George Strait, the Bristol Bay, the English Channel. The southern and western boundaries are delineated along the continental shelf.

The waters of the Celtic Sea are one of the richest areas of marine life and were designated by UNESCO as a «Biosphere Reserve» in 1988.

The climate of the reservoir will be equal to the temperate oceanic one. The water temperature in this area is noticeably lower than in the Adriatic Sea. Temperature conditions may vary depending on the season. In deeper layers, it varies from + 9 ° C to + 12 ° C. As for the salinity of water, it is at a more stable level - 35.7-36 ‰.

The main advantage of the reservoir is its favorable location in a kind of «wind rose», which is a constant source of a fairly strong wind. Due to this feature, local residents widely use wind generators in their activities.

In the summer season, the temperature profile of the waters is clearer and more vertical. Storms are frequent during the winter months, which also have a vertically mixed thermal environment. Studies show that the latter has become less constant due to global mixing that occurred about 6200 years ago.

Do you have a few more photos of the the Celtic Sea?