Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 31 Aug 2026:
- Most powerful swell: Friday 4 Sep, 1AM (local time) - 7.5ft (2.3m), 7s period, SW swell with 480 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 2.3m 7s and forecast to arrive on Friday (Sep 04) at 1AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.7m 5s period and expected on Saturday (Sep 05) at 4AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 1AM (Fri 4th Sep) | 7.5ft (2.3m) 7s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright folks, Rusty here, and I’ve got the goods for Trearddur Bay (Holy Island). Let’s just get this out there right now – the whole 16-day window is a bit of a struggle, so don’t be expecting much. I’ll run through it day by day.
To start, the water is sitting at a touch warmer than normal for this time of year, around 63°, which is a nice little bonus.
The first chance for a paddle comes on Monday, 31 August, but it’s a real dud. We’ve got a tiny 2 ft SW swell, only 8 seconds apart, with a cross-onshore wind at 12 mph. The combined energy is a weak 73, and it’s just poor, choppy surf. Not worth the wet suit.
Tuesday, 1 September, is a no-go. The morning brings a clean onshore wind, but the swell is even smaller and the period is a pathetic 4 seconds – just 23 in energy. The afternoon has a little more size at 4 ft, but the wind is onshore and strong at 19 mph, and the energy is still only 61. It’s messy.
Wednesday, 2 September, offers a bit more size – 5 ft in the afternoon from SSW, 6 seconds, with 194 in energy – but it’s a fresh cross-onshore and lumpy. Still poor.
Thursday, 3 September, is more of the same. Morning has 4 ft onshore, moderate energy at 102, but it’s poor. The afternoon drops off.
Friday, 4 September, has a 5 ft WSW swell in the morning, but the wind is a fresh cross-onshore at 22 mph, making it lumpy. The energy is 129, but it’s just not clean.
Saturday, 5 September, is a total write-off. The morning is barely 1 ft, and the afternoon is a tiny 0.3 ft with a 13-second period, but the wind is still cross-onshore. Energy is down to 11. It’s a flat, frustrating day.
Sunday, 6 September, is similar – small, weak, and cross-onshore.
Monday, 7 September, almost shows a glimmer of hope in the afternoon. The wind swings to a light cross-offshore from the north at 6 mph, and it’s clean. But the swell is a pathetic 1 ft, energy at 10. It’s clean, but there’s nothing to ride.
Tuesday, 8 September, stays poor. The afternoon brings a 6 ft SSW swell, 6 seconds, and 204 energy, but it’s a fresh cross-onshore and lumpy.
Wednesday, 9 September, is the biggest swell of the window – 6 ft from SW in the afternoon, 6 seconds, 278 energy. But it’s onshore with a strong breeze at 28 mph. The size is there, but it’s a messy, blown-out onshore mess. That’s more for the kitesurfers than us.
Thursday, 10 September, the wind gets nasty – a gale force cross-onshore at 43 mph with 5 ft swell. Completely blown out. Avoid.
From Friday, 11 September, through to Tuesday, 15 September, the swell drops off to nothing – 0.3 ft or 0.7 ft, with energy below 10. The wind does get clean at times, like glassy conditions on Saturday, 12 September, morning, or clean cross-offshore on Sunday, 13 September, morning, but there’s genuinely no wave to ride. Even the last day, Tuesday, 15 September, is clean with a cross-offshore breeze, but it’s a 0.3 ft swell.
So, to be straight with you: there is no standout session in this 16-day stretch. It’s a long, flat, and often windy run. The only thing worth noting is the clean conditions on the 7th, 12th, 13th, and 15th, but without swell, they’re just pretty days. That’s the reality for Trearddur Bay right now. Forecasts can change, but for now, I’d say keep the board in the van.
Rusty.
Short Range ForecastLight rain (total 5mm), mostly falling on Tue night. Very mild (max 18°C on Wed night, min 15°C on Mon night). Winds increasing (light winds from the WNW on Tue night, strong winds from the S by Wed morning). | Days 5-7 Weather SummaryLight rain (total 9mm), mostly falling on Thu night. Very mild (max 19°C on Sun morning, min 13°C on Fri night). Winds decreasing (strong winds from the SSW on Thu afternoon, light winds from the W by Sat morning). | |||||||||||||||||||
Mon 31 | Tuesday 1 | Wednesday 2 | Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | ||||||||||||||
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 8 | SSW 7 | SW 4 | SSW 5 | SW 5 | SSW 5 | SSW 6 | SW 7 | SW 6 | SSW 6 | SW 7 | WSW 5 | WSW 5 | SSW 6 | SW 6 | SW 5 | SW 13 | S 4 | SSW 4 | SSW 5 |
Wave Graph | ||||||||||||||||||||
50 | 21 | 23 | 61 | 38 | 40 | 184 | 279 | 94 | 63 | 480 | 113 | 62 | 25 | 8 | 7 | 7 | 7 | 11 | 28 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | on | on | on | cross-on | cross-on | on | on | cross-on | cross | cross-on | cross-on | cross | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on |
High Tide | 1:15AM5.69m | 1:36PM5.36m | 1:53AM5.56m | 2:15PM5.23m | 2:36AM5.34m | 3:01PM5.01m | 3:30AM5.02m | 3:59PM4.75m | 4:41AM4.69m | 5:21PM4.55m | 6:18AM4.51m | 7:01PM4.59m | ||||||||
Low Tide | 7:04PM0.89m | 7:26AM0.78m | 7:42PM1.01m | 8:06AM0.98m | 8:25PM1.22m | 8:51AM1.28m | 9:16PM1.51m | 9:47AM1.66m | 10:23PM1.82m | 10:59AM2.01m | 11:50PM1.99m | 12:31PM2.14m | 1:25AM1.84m | |||||||
— | — | 6:26 | — | — | 6:28 | — | — | 6:30 | — | — | 6:31 | — | — | 6:33 | — | — | 6:35 | — | — | |
8:10 | — | — | 8:08 | — | — | 8:06 | — | — | 8:04 | — | — | 8:01 | — | — | 7:59 | — | — | 7:57 | — | |
mm | — | — | — | 1 | 2 | 2 | — | — | — | 1 | 8 | — | — | — | — | — | — | — | — | — |
Temp °C | 17 | 16 | 15 | 17 | 17 | 16 | 17 | 18 | 18 | 17 | 17 | 15 | 17 | 15 | 13 | 15 | 16 | 19 | 22 | 19 |
Feels °C | 13 | 13 | 10 | 12 | 16 | 11 | 12 | 15 | 13 | 12 | 12 | 9 | 12 | 11 | 12 | 12 | 12 | 13 | 17 | 14 |
Swell 1 Height (m) Direction Period (s) | SW 8 | SSW 7 | — | — | SW 5 | S 16 | SW 16 | SW 15 | SW 14 | SW 14 | — | SW 14 | SW 14 | SSW 6 | NNW 4 | SW 5 | SW 13 | SW 13 | SW 13 | SW 12 |
50 | 21 | — | — | 38 | 5 | 10 | 9 | 8 | 8 | — | 8 | 8 | 25 | 8 | 4 | 7 | 7 | 6 | 6 | |
Swell 2 Height (m) Direction Period (s) | N 5 | NNW 4 | — | — | — | — | — | — | — | — | — | SW 14 | SW 14 | SW 14 | SW 6 | NNW 4 | — | SW 13 | — | — |
7 | 4 | — | — | — | — | — | — | — | — | — | 8 | 8 | 8 | 8 | 1 | — | 7 | — | — | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | SW 14 | SW 13 | — | — | — | — |
— | — | — | — | — | — | — | — | — | — | — | — | — | — | 7 | 7 | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | WNW 4 | W 3 | SW 4 | SSW 5 | — | SSW 5 | SSW 6 | SW 7 | SW 6 | SSW 6 | SW 7 | WSW 5 | WSW 5 | NW 4 | — | — | SSW 3 | S 4 | SSW 4 | SSW 5 |
23 | 6 | 23 | 61 | — | 40 | 184 | 279 | 94 | 63 | 480 | 113 | 62 | 15 | — | — | 3 | 7 | 11 | 28 | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 51 | 51 | 290 | 319 | 246 | 260 | 278 | 323 | 285 | 292 | 101 | 368 | 280 | 179 | 155 | 186 | 179 | 252 | 297 | 275 |
Best forecast wave conditions in Anglesy | ||||||||||||||||||||
Best forecast wave conditions in United Kingdom | ||||||||||||||||||||
Header Global | ||||||||||||||||||||
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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.











