Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 13 Sep 2026:
- Most powerful swell: Friday 18 Sep, 10PM (local time) - 8ft (2.5m), 7s period, SW swell with 640 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 Friday (Sep 18) at 10PM. Winds are predicted to be 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 Wednesday (Sep 16) at 7AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 10PM (Fri 18th Sep) | 8ft (2.5m) 7s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright folks, let’s have a look at what Trearddur Bay (Holy Island) has got cooking over the next couple of weeks. I’ve got to be straight with you—this one’s a tough read. The water is sitting at a touch warmer than normal for this time of year, about 62°, but that’s about the only gift the ocean is giving us.
Honestly, for the entire 16-day window, there’s not a single moment I’d point you toward the water with a board. From Saturday the 12th right through to Sunday the 27th of September, every single entry is flagged as poor surf conditions. We’ve got a long stretch here with no real recommendations – over two weeks of flat or messy dribble.
Let’s break it down. On Saturday the 12th, we see a 6 ft swell from the southwest, but it’s got a short period of just 7 seconds and a fresh 22 mph onshore wind. The combined energy is moderate at 314, but it’s all windswell and blown out – not worth paddling out for.
Sunday the 13th drops right off to 2-2 ft, light cross-onshore winds, tiny wind ripples. Monday through the following week is more of the same: small cross-onshore chop, periods mostly under 6 seconds, and the combined energy rarely cracking 100. There’s a brief blip on Wednesday the 16th with a 5 ft swell from the NW and combined energy of 124, but again – fresh cross-shore winds and lumpy conditions kill it.
Even when we get a bump to 6 ft on Friday the 18th with 176 combined energy, the wind is howling onshore at 22 mph. And the following days just keep delivering strong onshore breeze and messy, lumpy seas. There’s a tiny moment on Wednesday the 23rd where the wind goes glassy in the morning, but with only 1.0 ft on offer and a combined energy of 2, you’d be better off sunbathing.
After that, it’s all tiny, weak, and mostly cross-onshore. The swell direction is all over the place – SW, W, NW, S – but none of it lines up with a clean, rideable wave. Trearddur Bay is a beginner-friendly, fairly exposed southwest-facing break, but even beginners need something to push them. For the whole second week, we’re looking at knee-high slop at best.
This blank run is pretty normal for the area when the conditions don’t line up. It tends not to stay poor forever, but this stretch is a long one. If you’ve got a kite, you might find something fun on the windier days – the beach setup could handle that. But for a paddle surfer? Leave the boards at home.
Stay patient, friends. The ocean will come back around.
Rusty
Short Range ForecastModerate rain (total 17mm), heaviest on Mon night. Very mild (max 19°C on Sat afternoon, min 14°C on Mon night). Winds increasing (calm on Sat night, strong winds from the SSW by Mon afternoon). | Days 5-7 Weather SummaryLight rain (total 3mm), mostly falling on Tue afternoon. Very mild (max 16°C on Tue afternoon, min 12°C on Wed morning). Mainly strong winds. | |||||||||||||||||||
Sat 12 | Sunday 13 | Monday 14 | Tuesday 15 | Wednesday 16 | Thursday 17 | Friday 18 | ||||||||||||||
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 | SSW 7 | SSW 6 | SW 6 | SSW 6 | SSW 4 | SSW 5 | SSW 6 | WSW 6 | WNW 5 | SW 6 | NW 5 | W 4 | WSW 4 | WNW 5 | W 5 | W 4 | SW 5 | SW 6 | SW 7 |
Wave Graph  | ||||||||||||||||||||
 kJ | 314 | 76 | 25 | 17 | 18 | 30 | 86 | 309 | 90 | 37 | 9 | 114 | 18 | 21 | 48 | 46 | 38 | 28 | 176 | 503 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | glassy | cross-on | cross-on | cross-on | cross-on | cross-on | on | cross-on | cross-on | cross | cross | cross-on | on | cross-on | cross-on | cross-on | on | on | on |
High Tide | 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 | |||||||
 |  | | | | |  |  | |  | | | | | | | | | |  | |
 | — | — | 6:47 | — | — | 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 | — | — | — | — | — | — | — | 17 | — | 1 | — | — | — | 2 | — | — | — | — | — | 7 |
Temp °C | 19 | 18 | 16 | 17 | 17 | 16 | 17 | 17 | 15 | 16 | 14 | 13 | 15 | 15 | 14 | 15 | 14 | 14 | 15 | 16 |
Feels °C | 17 | 19 | 16 | 17 | 15 | 13 | 12 | 12 | 11 | 12 | 7 | 8 | 10 | 11 | 8 | 10 | 8 | 7 | 8 | 9 |
Swell 1 Height (m) Direction Period (s) | — | SSW 7 | SSW 6 | SW 6 | — | — | — | — | — | SW 6 | SW 6 | SW 6 | N 5 | NNW 5 | SW 6 | — | — | NW 4 | — | — |
| kJ | — | 76 | 25 | 17 | — | — | — | — | — | 24 | 9 | 5 | 19 | 4 | 38 | — | — | 9 | — | — |
Swell 2 Height (m) Direction Period (s) | — | NW 4 | — | — | — | — | — | — | — | — | S 11 | SW 11 | SW 5 | — | — | — | — | — | — | — |
| kJ | — | 2 | — | — | — | — | — | — | — | — | 2 | 5 | 1 | — | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | SW 11 | — | — | — | — | — | — | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | 5 | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | SW 7 | — | — | — | SSW 6 | SSW 4 | SSW 5 | SSW 6 | WSW 6 | WNW 5 | NW 5 | NW 5 | W 4 | WSW 4 | WNW 5 | W 5 | W 4 | SW 5 | SW 6 | SW 7 |
| kJ | 314 | — | — | — | 18 | 30 | 86 | 309 | 90 | 37 | 63 | 114 | 18 | 21 | 48 | 46 | 38 | 28 | 176 | 503 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 323 | 0 | 51 | 179 | 246 | 246 | 246 | 301 | 51 | 548 | 195 | 179 | 187 | 246 | 283 | 285 | 586 | 376 | 503 | 792 |
Best forecast wave conditions in Anglesy | ||||||||||||||||||||
Best forecast wave conditions in United Kingdom | ||||||||||||||||||||
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Recent Eyeball Surf Reports for Wales - Anglesy
‘Porth Neigwl: Choppy waves hadn't tidied much (from what I could see in the dark.’
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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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