Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 12 Sep 2026:
- Best quality surf: Sunday 13 Sep, 1AM (local time) - 3ft (0.9m), 7s period, SSW swell with glassy winds.
- Most powerful swell: Saturday 19 Sep, 4AM (local time) - 8ft (2.5m), 7s period, SW swell with 696 kJ wave energy.
- Next surfable swell (1★+): Sunday 13 Sep, 1AM (local time) - 3ft (0.9m), 7s 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 Sunday (Sep 13) at 1AM. The primary swell is predicted to be 0.9m and 7s period with a secondary swell of 0.3m and 4s. 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 2.5m 7s and forecast to arrive on Saturday (Sep 19) at 4AM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.4m 5s period and expected on Wednesday (Sep 16) at 7AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 1AM (Sun 13th Sep) | 3ft (0.9m) 7s |
| Best Surf | 1AM (Sun 13th Sep) | 3ft (0.9m) 7s |
| Most Powerful | 4AM (Sat 19th Sep) | 8ft (2.5m) 7s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Rusty here, looking at Trearddur Bay (Holy Island).
Alright, to be straight with you, the next 16 days are a tough watch. Not a single good session on the cards. Every single forecast window is showing poor surf. It’s a long, quiet run, with some bigger swell showing up but never with the right wind.
It starts this Saturday, the 12th. There's a solid 8ft SW swell with moderate energy (547), but it’s getting hammered by a strong onshore wind at 28 mph and light rain. Total mess. Saturday afternoon drops to 6ft SW, still onshore at 22 mph. Unrideable. Sunday the 13th sees the wind go glassy calm in the morning, but with only a 2ft swell, it's too weak and flat to bother with.
From Monday the 14th right through to late September, it’s a constant run of lumpy, cross-onshore wind and choppy conditions. There's a bump on Wednesday the 17th with a 5ft SW swell and some moderate energy (175), but the fresh cross-shore wind messes it up. The water is about 62°, a touch warmer than usual for now, but that doesn't save it.
The biggest pulse comes on Sunday the 20th of September – a serious 13ft SW groundswell with very strong energy (2241). But it’s getting thrashed by a 25 mph cross-onshore wind. That’s a blown-out, dangerous mess only for experts, and honestly, it looks better for a kite than a surfboard.
The only clean window you get is Friday the 25th of September. A moderate cross-offshore wind and a 5ft SW swell (177 energy). It’s the cleanest we see, but the surf quality is still poor, and this spot is inconsistent. You’d be gambling on that one.
A long, dry spell like this is pretty normal for the area when the weather sets in. Don't force it. Forecasts can shift, but for now, just sit it out.
Rusty.
Short Range ForecastLight rain (total 7mm), mostly falling on Sat morning. Very mild (max 19°C on Sat afternoon, min 14°C on Mon night). Winds decreasing (strong winds from the SW on Sat morning, calm by Sat night). | Days 4-6 Weather SummaryLight rain (total 2mm), mostly falling on Tue night. Very mild (max 16°C on Tue afternoon, min 13°C on Tue night). Mainly strong winds. | ||||||||||||||||||||
Saturday 12 | Sunday 13 | Monday 14 | Tuesday 15 | Wednesday 16 | Thursday 17 | Friday 18 | |||||||||||||||
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 7 | SSW 7 | SSW 6 | SW 6 | SSW 3 | SSW 5 | SSW 5 | SSW 6 | WSW 6 | W 5 | NW 5 | SW 6 | W 11 | WSW 4 | W 5 | W 5 | W 5 | WSW 5 | SW 4 | SSW 7 |
Wave Graph  | |||||||||||||||||||||
 kJ | 547 | 287 | 76 | 26 | 18 | 8 | 31 | 99 | 293 | 135 | 49 | 110 | 6 | 2 | 31 | 110 | 65 | 55 | 35 | 36 | 537 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | glassy | glassy | on | cross-on | on | cross-on | on | cross-on | cross-on | cross | cross | cross-on | on | cross | cross-on | cross-on | on | on | on |
High Tide | 11:50AM5.61m | 00:04AM5.91m | 12:25PM5.56m | 00:40AM5.77m | 1:00PM5.44m | 1:15AM5.55m | 1:34PM5.27m | 1:50AM5.26m | 2:09PM5.06m | 2:27AM4.94m | 2:48PM4.82m | 3:10AM4.60m | 3:35PM4.56m | ||||||||
Low Tide | 5:49PM0.68m | 6:16AM0.50m | 6:26PM0.74m | 6:52AM0.70m | 7:02PM0.91m | 7:27AM0.99m | 7:38PM1.17m | 8:03AM1.34m | 8:16PM1.50m | 8:40AM1.73m | 8:59PM1.87m | 9:24AM2.12m | 9:53PM2.22m | ||||||||
 |  |  | | | |  | |  | |  | | | | | | | | | | | |
 | 6:45 | — | — | 6:47 | — | — | 6:48 | — | — | 6:50 | — | — | 6:52 | — | — | 6:54 | — | — | 6:56 | — | — |
 | — | 7:42 | — | — | 7:39 | — | — | 7:37 | — | — | 7:35 | — | — | 7:32 | — | — | 7:30 | — | — | 7:28 | — |
mm | 2 | — | — | — | — | — | — | — | 5 | — | — | 1 | — | — | 1 | — | — | — | — | — | 2 |
Temp °C | 17 | 19 | 18 | 16 | 16 | 17 | 16 | 17 | 17 | 15 | 16 | 14 | 14 | 15 | 14 | 13 | 15 | 14 | 14 | 15 | 16 |
Feels °C | 11 | 17 | 18 | 17 | 16 | 15 | 12 | 12 | 11 | 10 | 11 | 7 | 8 | 10 | 9 | 6 | 8 | 7 | 9 | 8 | 9 |
Swell 1 Height (m) Direction Period (s) | — | — | SSW 7 | SSW 6 | SW 6 | — | — | — | — | — | — | SW 6 | SW 6 | SW 5 | NW 4 | SW 6 | — | — | — | — | — |
| kJ | — | — | 76 | 26 | 18 | — | — | — | — | — | — | 9 | 6 | 1 | 3 | 65 | — | — | — | — | — |
Swell 2 Height (m) Direction Period (s) | — | — | NW 4 | — | — | — | — | — | — | — | — | S 11 | SW 11 | — | NNW 5 | — | — | — | — | — | — |
| kJ | — | — | 2 | — | — | — | — | — | — | — | — | 2 | 5 | — | 2 | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | W 11 | — | — | — | — | — | — | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | 2 | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | SW 7 | SW 7 | — | — | — | SSW 3 | SSW 5 | SSW 5 | SSW 6 | WSW 6 | W 5 | NW 5 | NW 5 | NW 5 | WSW 4 | W 5 | W 5 | W 5 | WSW 5 | SW 4 | SSW 7 |
| kJ | 547 | 287 | — | — | — | 8 | 31 | 99 | 293 | 135 | 49 | 110 | 103 | 42 | 31 | 110 | 65 | 55 | 35 | 36 | 537 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 251 | 323 | 0 | 51 | 179 | 246 | 246 | 246 | 280 | 51 | 548 | 195 | 326 | 284 | 280 | 285 | 284 | 285 | 278 | 284 | 895 |
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.
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