Trearddur Bay (Holy Island) Surf Break

Lat Long: 53.28° N 4.62° W

Trearddur Bay (Holy Island) Surf Forecast and Surf Report

Issued: 6 am 25 Aug 2026 (local time)

Forecast update in  hr  min

Today's Trearddur Bay (Holy Island) sea temperature is
17.2°C
1.6° 

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: Tuesday 1 Sep, 10AM (local time) - 10ft (3.0m), 8s period, SW swell with 1,334 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 8s and forecast to arrive on Tuesday (Sep 01) 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 1.3m 5s period and expected on Monday (Aug 31) at 4AM.

Wave TypeTime (BST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful10AM (Tue 1st Sep)10ft (3.0m) 8s

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


The Lowdown

Hey folks, Rusty here. Let’s be straight with this one – Trearddur Bay (Holy Island) is looking at a grim run for the next 16 days. There is no surf worthy of a paddle-out until around the 9th of September, and even that is a huge question mark. We’re talking well over a week of flat or junk swell and messy wind. Let’s get into the details.

The water temp is sitting at 63°F, which is about a touch warmer than normal for the time of year, so you won’t need the thickest rubber if you do get out.

From Tuesday the 25th of August, through to the end of the month and into the first week of September, it’s a write-off. Swell heights mostly below 2 ft, with period windswell under 8 seconds, and wind is either cross-off, cross-on, or howling onshore. The combined wave energy is weak, often well under 100 (10–73 range). For a place that’s “fairly exposed” to SW swell, this is a real drought. The only positive is that a few morning windows show clean conditions, but there’s simply no push.

The 1st of September shows a spike – 10 ft swell, but it’s short-period (8 seconds), combined energy 1334, and wind is screaming onshore or cross-onshore at 18–25 mph. For an exposed beach break setup like this, that’s not surf – that's a washing machine for experts only, and even then the wind will destroy any shape. Kite surfers might find some fun, but paddle surfing? Forget it.

Moving into the 5th of September, we get some size again (6 ft, 8-second period, combined energy 435), but the wind is still fresh cross-onshore, so quality stays low. The 7th of September is the one small glimmer: on the Monday morning, we have 6 ft SW swell with a 6-second period, and a solid cross-off wind from the N at 18 mph. That wind direction is actually offshore here. Combined energy is 188 – moderate. It’ll be clean, but the period is short, so waves will be soft and lumpy. Not a standout, just the best of a bad lot.

Then the 8th and 9th of September roll in. The 8th Tuesday afternoon sees another 10 ft pulse (8 seconds, combined energy 988), but again with strong cross-onshore winds. Wednesday the 9th morning is the only day the guidance even gives a marginal nod. Swell height 8 ft, period 8 seconds, combined energy 908, but the wind is a gentle cross-onshore from the west. That’s too big for beginners, big for intermediates, and on a beach break with 8-second period and cross-onshore wind – it's lumpy and challenging.

Bottom line: There is no standout session in this 16-day window. Trearddur Bay is inconsistent and the conditions just refuse to line up. The one potential window is the morning of the 7th of September for cleaner, smaller waves, or very early on the 9th if you're desperate and expert. Otherwise, the forecast is a write-off for quality surf. It’s the kind of run that doesn’t happen often here, but when it does, you just have to wait for the next system to shift.

Stay patient. Rusty.

Short Range Forecast

Light rain (total 6mm), mostly falling on Thu afternoon. Warm (max 20°C on Tue afternoon, min 16°C on Tue morning). Winds decreasing (fresh winds from the E on Tue night, light winds from the ESE by Wed morning).

Days 4-6 Weather Summary

Heavy rain (total 22mm), heaviest during Sun afternoon. Very mild (max 17°C on Fri afternoon, min 13°C on Sun night). Winds increasing (light winds from the WNW on Sat night, strong winds from the WNW by Sun night).

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
0.4
SW
8
0.3
SSW
8
0.2
SSW
7
0.2
SSW
7
0.2
SSW
7
0.8
SSW
4
1.4
SW
5
1.1
SW
7
0.9
SW
7
1
SSW
6
1.3
SSW
7
1.2
SW
8
0.7
SW
8
0.6
SSW
7
0.9
SSW
7
0.7
SW
7
0.8
SW
4
2.2
SW
6
Wave Graph
Metric surfscale
Energy kJ
7
7
7
17
12
5
6
4
24
94
140
75
73
142
192
62
35
76
51
27
364
Wind (km/h)
25
E
15
ENE
25
E
20
E
10
N
15
NE
5
SSE
10
NNE
20
SSW
25
SW
20
SSW
20
WSW
25
SW
20
WSW
10
NW
10
SSW
25
SSW
35
NW
40
WNW
25
SW
30
WNW
Wind State
cross-off
off
cross-off
cross-off
cross-off
off
cross-on
cross-off
on
on
cross-on
on
on
on
cross
on
cross-on
cross-off
cross
on
cross-on
High Tide
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
cloud
cloud
cloud
light rain
clear
part cloud
light rain
rain showers
cloud
light rain
part cloud
rain showers
rain showers
rain showers
rain showers
rain showers
thunderstorm
thunderstorm
clear
rain showers
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
1
1
4
3
3
3
1
3
1
5
3
1
Temp °C
18
20
20
18
20
19
17
17
17
16
17
17
17
17
17
16
17
16
13
16
15
Feels °C
16
17
13
18
19
18
17
17
15
13
15
16
12
14
14
15
13
12
5
10
8
  • Map Icons:
  • Break
  • 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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