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 04 Sep 2026 (local time)

Forecast update in  hr  min

Today's Trearddur Bay (Holy Island) sea temperature is
16.9°C
1.4° 

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 4 Sep 2026:

  • Most powerful swell: Thursday 10 Sep, 1AM (local time) - 8ft (2.5m), 7s period, SSW swell with 553 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 2.5m 7s and forecast to arrive on Thursday (Sep 10) at 1AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.5m 6s period and expected on Wednesday (Sep 09) at 10AM.

Wave TypeTime (BST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful 1AM (Thu 10th Sep)8ft (2.5m) 7s

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


The Lowdown

Alright folks, Rusty here. Let’s have a look at what’s on offer for Trearddur Bay over the next couple of weeks.

Honestly, it’s a tough stretch. The outlook for Trearddur Bay (Holy Island) is pretty grim for the first nine days. We’ve got a run of poor surf conditions from Friday the 4th all the way through to the morning of Saturday the 13th of September. That’s a solid gap with nothing worth paddling out for. The wind is almost always cross-onshore or onshore, often strong, and the wave energy is weak to moderate at best, with combined energy figures mostly in the double digits or low triple digits (like 176, 139, 60). The swell is short period, around 4 to 7 seconds, so it’s weak and messy. The one standout window is a brief moment on the morning of Sunday the 13th of September.

Sunday, 13th September – The Best Bet
On Sunday morning, we finally get a bit of a break. The swell is 4 ft from the SW, with a period of 5 seconds, and the combined energy is a modest 68. The wind goes light, from the N at 6 mph, and it’s cross-offshore. That means clean conditions. It’s surfable, but very ordinary. Trearddur Bay is a beginner spot, inconsistent, and it’s fairly exposed to the SW swell direction, which matches the guidance’s optimum direction. The water temperature is about average for this time of year, nothing unusual. This is the only session that scrapes a recommendation, but it's not a classic. The afternoon on Sunday gets a bit bigger at 5 ft, but the wind turns cross-shore and the energy jumps to 134, making it a bit lumpy.

Monday, 14th September – Big But Not Good
Then Monday the 14th sees a spike in size – 8 ft from the SW, with a period of 7 seconds and combined energy of 539. That’s moderate-to-strong energy, but it’s all onshore wind from the SW, so it’s a washing machine. That size is too big for beginners and only okay for experts, but with onshore wind, it’s just a mess.

After that, the last few days of the outlook (15th to 19th September) drop right off. Tiny swell, 0.3 ft to 3 ft, and weak energy figures (1 to 24). The wind is a mix of cross-on, cross, or light, but the swell is too small to surf. The 17th and 18th are flat with just a ripple.

So, if you’re desperate, the morning of Sunday the 13th is your window. It’s clean, but the waves will be small and ordinary. Otherwise, it’s a long wait for something better. Forecasts can change, but right now, it’s a blank run for Trearddur Bay.

Rusty.

Short Range Forecast

Moderate rain (total 14mm), heaviest on Thu night. Warm (max 20°C on Sun afternoon, min 13°C on Fri night). Winds decreasing (fresh winds from the WSW on Fri morning, light winds from the SW by Sat morning).

Days 4-6 Weather Summary

Light rain (total 5mm), mostly falling on Mon night. Very mild (max 17°C on Sun night, min 12°C on Mon night). Mainly strong winds.

Friday
4
Saturday
5
Sunday
6
Monday
7
Tuesday
8
Wednesday
9
Thursday
10
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)
1.7
WSW
5
1.4
SW
6
1.5
W
5
1
W
5
0.6
SW
6
1
SSW
4
1.1
SSW
5
1.4
SSW
6
1.7
SSW
6
0.3
SW
14
1.2
SW
5
1.7
WSW
6
2.2
W
6
1.8
W
6
1.7
WNW
6
1.2
W
5
1.1
SW
5
2.5
SSW
7
1.3
SW
7
1
SW
7
1.1
W
4
Wave Graph
Metric surfscale
Energy kJ
168
123
120
46
26
42
55
119
202
40
63
211
366
214
201
71
55
553
169
104
46
Wind (km/h)
40
WSW
35
WSW
35
W
20
WSW
25
SW
30
S
30
S
30
S
35
SSW
25
W
30
SSW
30
WSW
40
W
35
W
35
W
35
W
30
SW
45
SSW
25
WSW
25
SW
35
WNW
Wind State
cross-on
cross-on
cross-on
cross-on
on
cross-on
cross-on
cross-on
on
cross-on
on
cross-on
cross-on
cross-on
cross-on
cross-on
on
cross-on
cross-on
on
cross
High Tide
3:59PM4.75m
4:41AM4.69m
5:21PM4.55m
6:18AM4.51m
7:01PM4.59m
7:54AM4.65m
8:23PM4.91m
9:02AM4.96m
9:21PM5.29m
9:53AM5.26m
10:08PM5.63m
10:36AM5.47m
10:49PM5.85m
Low Tide
9:47AM1.66m
10:23PM1.82m
10:59AM2.01m
11:50PM1.99m
12:31PM2.14m
1:25AM1.84m
1:57PM1.96m
2:38AM1.44m
3:00PM1.61m
3:33AM1.02m
3:50PM1.24m
4:19AM0.68m
4:32PM0.95m
part cloud
clear
clear
clear
part cloud
rain showers
cloud
part cloud
part cloud
part cloud
part cloud
rain showers
clear
light rain
part cloud
part cloud
cloud
mod rain
cloud
rain showers
rain showers
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
6:31
6:33
6:35
6:37
6:39
6:39
6:41
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
8:01
7:59
7:57
7:53
7:52
7:50
7:46
 mm
3
4
1
10
1
1
Temp °C
15
17
16
14
14
15
17
20
17
15
16
16
14
15
14
14
16
16
17
17
16
Feels °C
8
11
9
11
10
10
10
14
12
11
11
7
6
8
7
7
12
11
14
13
10
  • 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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