
Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 3 Sep 2026:
- Best quality surf: Thursday 10 Sep, 1PM (local time) - 4.5ft (1.3m), 6s period, SSW swell with glassy winds.
- Most powerful swell: Thursday 3 Sep, 7PM (local time) - 5.5ft (1.7m), 6s period, SW swell with 226 kJ wave energy.
- Next surfable swell (1★+): Thursday 10 Sep, 1PM (local time) - 4.5ft (1.3m), 6s period with SSW swell.
Best Forecast Surf Conditions for Trearddur Bay (Holy Island) this week:
The surf forecast for Trearddur Bay (Holy Island) over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Thursday (Sep 10) at 1PM. The primary swell is predicted to be 1.3m and 6s period. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Trearddur Bay (Holy Island) in the next 16 days are 1.7m 6s and forecast to arrive on Thursday (Sep 03) at 7PM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.6m 6s period and expected on Wednesday (Sep 09) at 1AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 1PM (Thu 10th Sep) | 4.5ft (1.3m) 6s |
| Best Surf | 1PM (Thu 10th Sep) | 4.5ft (1.3m) 6s |
| Most Powerful | 7PM (Thu 3rd Sep) | 5.5ft (1.7m) 6s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright folks, Rusty here. Gotta be straight with you – looking at the next 16 days for Trearddur Bay (Holy Island), it’s a tough stretch. The water is sitting at 62°, which is a touch warmer than normal for this time of year, but that's about the only thing that's playing ball. We’ve got a long, dry spell of poor surf conditions ahead. The first real glimmer of anything rideable is a long way off, and even then, it’s not much.
Let’s be honest, the first week is a write-off. Thursday the 3rd kicks off with a 4 ft SW swell (155 energy), but with a 16 mph SW wind howling onshore, it’s just messy. That pattern holds through the whole first week: wind mostly onshore or cross-onshore, periods short and weak. The swell bumping up to 6 ft on Friday the 4th and again on Tuesday the 8th (178 energy) is just blown out junk. That 5 ft on Sunday the 6th (164 energy) is raw and lumpy with fresh cross-onshore wind. Not worth the paddle out.
We do get a bit of a pulse mid-week. Thursday the 10th morning shows a 6 ft SSW swell (211 energy) – that’s the biggest number we see – but it’s still under a gentle cross-onshore breeze. The period is only 6 seconds, so it’s weak, short-period wind swell. It’s listed as "poor surf conditions." The afternoon of the 10th goes glassy-light with a 3 ft swell, but again, the quality just isn't there.
After that, it’s a long, slow drain. From the 11th of September right through to the 18th, we’re looking at swell heights dropping under 2 ft, with most days showing zero energy. The 13th and 14th finally show some clean offshore winds from the NE and NNE, but the swell is a flat 0.3 ft. That’s not surf, that’s a lake.
The standout – if you can call it that – is the morning of Thursday, 10th September. It’s the only sniff of moderate wave energy (211) in the whole forecast. The 6 ft SSW swell gives the bay the most size, and while the wind is cross-onshore, it’s only a light 9 mph breeze. The swell direction is SW, which is the optimum for Trearddur Bay. It’s not clean, it’s not perfect, but it’s the only window where the size is there to make something of a session. Expect crowds to be possible, as it’s the only real option in a long, dry spell.
For everything else, the setup is too small, too windy, or both. Honestly, with the strong winds and poor wave quality on the bigger days, this looks more interesting for kite surfing than paddle surfing for most of the period. It’s a tough one to swallow, but sometimes the ocean just gives you a rest.
Stay patient, lads. This blank run is normal for the area when the patterns lock in like this. Forecasts can change.
Rusty.
Short Range ForecastModerate rain (total 14mm), heaviest on Thu night. Very mild (max 18°C on Thu morning, min 14°C on Thu night). Mainly strong winds. | Days 4-6 Weather SummaryLight rain (total 7mm), mostly falling on Mon night. Warm (max 20°C on Sun afternoon, min 12°C on Mon night). Mainly fresh winds. | ||||||||||||||||||||
Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | |||||||||||||||
AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | |
Swell Height Map | |||||||||||||||||||||
Wave Height (m) Direction Period (s) | SW 7 | SW 6 | SSW 7 | WSW 5 | SW 5 | WNW 5 | SW 6 | SW 3 | SSW 5 | SSW 5 | SSW 6 | SSW 6 | WNW 4 | SW 6 | WSW 6 | W 6 | SW 6 | SW 7 | NW 5 | W 4 | SW 4 |
Wave Graph | |||||||||||||||||||||
147 | 123 | 145 | 149 | 110 | 54 | 23 | 9 | 40 | 53 | 158 | 164 | 32 | 46 | 159 | 134 | 56 | 18 | 68 | 14 | 40 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | cross-on | cross-on | on | cross-on | on | on | cross-on | cross-on | cross-on | on | cross-on | cross-on | cross-on | cross-on | cross-on | cross | cross | cross-on | on |
High Tide | 3:01PM5.01m | 3:30AM5.02m | 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 | ||||||||
Low Tide | 9:16PM1.51m | 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 | |||||||||
6:30 | — | — | 6:31 | — | — | 6:33 | — | — | 6:35 | — | — | 6:37 | — | — | 6:39 | — | — | 6:39 | — | — | |
— | 8:04 | — | — | 8:01 | — | — | 7:59 | — | — | 7:57 | — | — | 7:53 | — | — | 7:52 | — | — | 7:50 | — | |
mm | — | 2 | 12 | — | — | — | — | — | — | — | — | — | — | — | 7 | — | — | — | — | — | 2 |
Temp °C | 18 | 17 | 16 | 15 | 17 | 16 | 14 | 14 | 15 | 18 | 20 | 17 | 14 | 16 | 16 | 14 | 15 | 14 | 13 | 14 | 15 |
Feels °C | 14 | 12 | 12 | 8 | 11 | 10 | 11 | 10 | 11 | 11 | 14 | 12 | 10 | 10 | 10 | 7 | 8 | 7 | 7 | 11 | 11 |
Swell 1 Height (m) Direction Period (s) | SW 14 | — | WNW 4 | SW 14 | SW 14 | SW 6 | NW 5 | NNW 4 | SW 13 | SW 13 | SW 13 | SW 12 | SSW 6 | NW 4 | SW 11 | SW 7 | SW 6 | SW 7 | SW 5 | N 5 | — |
8 | — | 7 | 8 | 8 | 38 | 18 | 2 | 7 | 7 | 6 | 6 | 22 | 8 | 5 | 44 | 56 | 18 | 5 | 12 | — | |
Swell 2 Height (m) Direction Period (s) | — | — | SW 14 | — | — | SW 7 | SW 14 | WNW 4 | — | — | — | — | WSW 13 | SW 12 | — | — | — | — | — | — | — |
— | — | 8 | — | — | 2 | 7 | 1 | — | — | — | — | 17 | 23 | — | — | — | — | — | — | — | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | SW 14 | SW 14 | SW 13 | — | — | — | — | — | — | — | — | — | — | — | — | — |
— | — | — | — | — | 8 | 7 | 7 | — | — | — | — | — | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | SW 7 | SW 6 | SSW 7 | WSW 5 | SW 5 | WNW 5 | SW 6 | SW 3 | SSW 5 | SSW 5 | SSW 6 | SSW 6 | WNW 4 | SW 6 | WSW 6 | W 6 | NW 5 | NNW 6 | NW 5 | W 4 | SW 4 |
147 | 123 | 145 | 149 | 110 | 54 | 23 | 9 | 40 | 53 | 158 | 164 | 32 | 46 | 159 | 134 | 31 | 179 | 68 | 14 | 40 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 288 | 293 | 51 | 306 | 548 | 179 | 51 | 246 | 179 | 238 | 446 | 281 | 51 | 314 | 292 | 280 | 548 | 179 | 358 | 273 | 194 |
Best forecast wave conditions in Anglesy | |||||||||||||||||||||
Best forecast wave conditions in United Kingdom | |||||||||||||||||||||
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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.










