Trearddur Bay (Holy Island) Surf Break

Lat Long: 53.28° N 4.62° W

Trearddur Bay (Holy Island) Surf Forecast and Surf Report

Issued: 12 am 25 Aug 2026 (local time)

Forecast update in  hr  min

Today's Trearddur Bay (Holy Island) sea temperature is
17.1°C
1.5° 

Trearddur Bay (Holy Island) surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.


Trearddur Bay (Holy Island) surf forecast from 25 Aug 2026:

  • Most powerful swell: Monday 31 Aug, 10AM (local time) - 10ft (3.0m), 7s period, WSW swell with 705 kJ wave energy.

Best Forecast Surf Conditions for Trearddur Bay (Holy Island) this week:

The most powerful waves expected at Trearddur Bay (Holy Island) in the next 16 days are 3.0m 7s and forecast to arrive on Monday (Aug 31) at 10AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.9m 5s period and expected on Wednesday (Aug 26) at 1AM.

Wave TypeTime (BST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful10AM (Mon 31st Aug)10ft (3.0m) 7s

Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.


The Lowdown

Alright folks, Rusty here. Let's be straight with you – it’s looking bleak for the Holy Island coast over the next two and a half weeks. This is one of those stretches where you might want to take up a new hobby. There's a long, long gap with barely a ripple worth mentioning from now all the way into the first week of September.

The only break we’ve got on the cards is Trearddur Bay (Holy Island). The water is sitting at 63°F and the anomaly says it’s a touch warmer than normal for this time of year, which is nice on the skin even if the surf isn't.

Alright, let’s walk through it. From Monday the 24th right through until Wednesday morning the 2nd of September, it’s a write-off. We’re talking nearly ten days of flatness, onshore junk, or mismatched wind. You’ll see tiny 0.3ft slop with a combined energy of just 3, and a lot of cross-off or onshore breezes. There’s a moment on Wednesday afternoon the 26th where the wind goes light and cross, but the swell is only 1.0ft with a short period of 8 seconds and energy of 17. It just doesn’t have the juice. Even a glassy morning on the 27th only offers 0.3ft – frustrating.

Friday the 28th morning does kick up to 4ft from the SSW, but the period is a short 7 seconds and the combined energy climbs to 207 (moderate). Problem is, it’s blowing onshore at 19 mph. That’s messy, not magic.

Now, there is a glimmer. Wednesday afternoon the 2nd of September is the only true standout in this whole outlook. It’s a glassy calm afternoon with a clean 7ft SSW swell, period of 6 seconds, and combined energy of 341 (moderate). But here’s the kicker: that swell size is over 8ft – and at Trearddur Bay, that puts it squarely in the expert zone. It’s going to be big and powerful, and the short period (6 seconds) means it’ll be a bit lumpy and hard to manage. Only for the brave and the skilled.

After that, Thursday the 3rd has a cleaner 5ft NW groundswell with a cross-off breeze, which is a nicer size for stronger intermediates, but the quality drops quickly. Then from Friday the 4th through to the end of the outlook, it’s all cross-shore chop with onshore winds and lumpy conditions. There is a monster pulse on Monday the 7th of September – a 16ft to 18ft SW groundswell with a period of 10 seconds and immense energy (4648 to 5957). That is very strong energy. But the file says it’s predicted to be too big for this break, and the wind is marginal. That’s one for the big wave chargers elsewhere, if it cleans up.

So, bottom line: mark your calendar for Wednesday the 2nd of September if you’re an expert looking for a heavy, glassy challenge. For everyone else, it’s a long wait or a trip elsewhere. The setup through most of the second week looks more interesting for kite surfing than paddle surfing, with strong cross-shore winds and solid swell.

Stay patient.

Rusty.

Short Range Forecast

Moderate rain (total 13mm), heaviest on Wed morning. Warm (max 21°C on Tue night, min 14°C on Mon night). Winds decreasing (fresh winds from the E on Tue night, calm by Wed afternoon).

Days 4-6 Weather Summary

Heavy rain (total 58mm), heaviest during Thu night. Very mild (max 18°C on Fri night, min 15°C on Sat morning). Winds increasing (light winds from the W on Thu night, fresh winds from the S by Sun morning).

Tuesday
25
Wednesday
26
Thursday
27
Friday
28
Saturday
29
Sunday
30
Monday
31
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.1
SW
13
0.1
SW
13
0.2
SSW
8
0.3
SSW
8
0.3
SSW
8
0.2
SSW
7
0.2
SSW
7
0.2
SSW
7
0.2
SSW
6
1.5
SSW
5
1
SSW
7
0.7
SSW
7
0.7
SW
6
0.5
SSW
6
0.6
SW
8
1.3
SSW
5
2
SSW
7
2
SW
6
3
WSW
7
1.9
WSW
6
1.1
SW
6
Wave Graph
Metric surfscale
Energy kJ
7
7
7
13
12
5
6
5
4
116
85
40
43
21
49
65
332
301
705
280
69
Wind (km/h)
25
E
20
NE
30
E
15
E
5
NNE
15
ENE
15
ESE
10
NE
20
SW
30
W
20
SW
25
W
25
SSW
15
SW
20
WSW
40
S
40
SSW
45
W
45
WNW
30
W
35
SW
Wind State
cross-off
off
cross-off
cross-off
glassy
off
cross-off
off
on
cross-on
on
cross-on
cross-on
on
cross-on
cross-on
on
cross-on
cross-on
cross-on
on
High Tide
9:52AM4.67m
9:59PM5.08m
10:26AM4.89m
10:33PM5.32m
10:57AM5.08m
11:04PM5.51m
11:27AM5.23m
11:36PM5.65m
11:57AM5.33m
00:07AM5.72m
12:28PM5.40m
00:40AM5.74m
1:01PM5.41m
1:15AM5.69m
Low Tide
3:46PM1.80m
4:11AM1.47m
4:21PM1.52m
4:43AM1.19m
4:52PM1.28m
5:14AM0.96m
5:23PM1.07m
5:44AM0.80m
5:55PM0.94m
6:16AM0.70m
6:28PM0.87m
6:50AM0.69m
7:04PM0.89m
part cloud
cloud
light rain
rain showers
part cloud
part cloud
light rain
light rain
heavy rain
heavy rain
part cloud
rain showers
rain showers
part cloud
part cloud
rain showers
thunderstorm
thunderstorm
part cloud
part cloud
part cloud
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
6:13
6:16
6:18
6:20
6:20
6:22
6:24
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
8:24
8:22
8:20
8:17
8:15
8:13
8:10
 mm
4
5
1
3
36
12
1
2
4
3
5
Temp °C
18
20
21
17
19
19
18
17
16
16
17
18
17
18
18
16
16
15
15
17
17
Feels °C
16
16
15
17
19
18
17
17
16
12
15
16
15
16
15
9
9
9
7
13
12
  • Map Icons:
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  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
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Information about the Trearddur Bay (Holy Island) Surf forecast

The above surf forecast table for Trearddur Bay (Holy Island) provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Trearddur Bay (Holy Island) can be found by selecting the local surf guide option on the grey menu. Our Trearddur Bay (Holy Island) surf forecast is unique since it includes wave energy (power) that defines the real feel of the surf rather than just the height or the period. If you surf the same spot (Trearddur Bay (Holy Island)) regularly then make a mental note of the wave energy from the surf forecast table each time you go. Very soon you may start to choose your surf days based on the wave energy alone combined with our forecast of favourable offshore wind conditions. Our star ratings will help here and of course you will also find the usual wave height and period predictions on our surf forecasts as well as a full break down of the swell components under our advanced users option (to reveal that, click the little Einstein character under the tide times).

Further information to help with frequently asked questions about our surf forecast for Trearddur Bay (Holy Island) may be found under the help tab on the top menu and also by moving your mouse over the question marks on the surf forecast table itself. Please always bear in mind that the forecast is for near-shore open water and local factors at each surf break influence the actual breaking wave height, such as the beach / reef profile, water depths offshore and shelter.

Are you planning a holiday in Anglesy? If you are looking for accommodation near Trearddur Bay (Holy Island), camping, hotels and holiday cottages in Anglesy, consider staying in Holyhead which is 4 km (2 miles) away. Other places in and around Anglesy where you can find information about places to rent, and car hire include Anglesey which is 7 km (4 miles) away, Bangor, Porthmadog and Llandudno.

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