Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 7 Sep 2026:
- Most powerful swell: Saturday 12 Sep, 7PM (local time) - 7ft (2.2m), 7s period, SW swell with 412 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 2.2m 7s and forecast to arrive on Saturday (Sep 12) at 7PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.7m 6s period and expected on Wednesday (Sep 09) at 1AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 7PM (Sat 12th Sep) | 7ft (2.2m) 7s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright mate, Rusty here. I’ll level with you – this 16-day stretch is a tough one for Trearddur Bay. There’s only one brief window that’s even worth a look, and it comes with a big caveat.
Trearddur Bay (Holy Island) is a beginner-friendly, fairly exposed spot that needs a SW swell, but for the first nine days, it’s a blowout. Monday the 7th starts with a weak, short-period 3ft SW windswell and a solid 12 mph onshore – messy, no good. That theme sticks around all week: Tuesday the 8th brings a 22 mph cross-onshore wind with waist-high, lumpy 4ft waves, and Wednesday the 9th drops right off to nearly flat. Thursday the 10th afternoon bumps up to 6ft from the SSW, but with a strong 25 mph onshore, it’s a total washout. The weekend of the 12th and 13th offers no relief – Saturday the 12th afternoon pushes 7ft but with howling 28 mph onshores and rain, just terrible. Sunday drops back to small, weak surf.
The water temp is sitting at 62°, which is a touch warmer than normal for this time of year, but you won't be feeling it through the wind.
The one window that shows any hope at all is Thursday the 17th of September. We get a pulse of 7ft SSW groundswell (6 second period). That’s a size that’s too much for beginners. The wind is light and cross-shore from the SE at 6 mph, so the surface stays fairly clean, but the comments say it’s “marginal” – likely a tide or bank issue. The combined energy is strong at 333. For an experienced surfer who knows the sandbanks, a clean 7ft day is the only real standout in this whole forecast. The following days drop off hard again, with a long-period 0.3ft SW groundswell on the 21st and 22nd, totally flat and not worth the paddle.
So yeah, it’s pretty grim. A blank run like this is more normal for the area when the Atlantic isn’t playing ball. I’d mark Thursday 17th morning in your calendar, but keep expectations low. The rest is a write-off.
Rusty
Short Range ForecastLight rain (total 4mm), mostly falling on Mon afternoon. Very mild (max 16°C on Mon afternoon, min 13°C on Mon night). Winds decreasing (strong winds from the SW on Mon afternoon, light winds from the SW by Wed afternoon). | Days 4-6 Weather SummaryModerate rain (total 10mm), heaviest on Sat afternoon. Very mild (max 17°C on Thu night, min 14°C on Thu night). Winds increasing (light winds from the S on Fri afternoon, strong winds from the SSW by Sat afternoon). | ||||||||||||||||||||
Monday 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | Sunday 13 | |||||||||||||||
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 14 | SW 5 | SW 7 | W 5 | WNW 5 | SW 6 | SW 7 | SW 7 | SW 4 | SW 4 | SSW 6 | SW 6 | SW 6 | SW 6 | SW 3 | SSW 5 | SSW 6 | SW 7 | SW 7 | SSW 6 | SSW 5 |
Wave Graph  | |||||||||||||||||||||
 kJ | 34 | 94 | 163 | 81 | 105 | 5 | 19 | 14 | 11 | 40 | 176 | 120 | 33 | 19 | 12 | 116 | 406 | 173 | 44 | 35 | 46 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | cross-on | cross-on | cross-on | cross | cross | on | on | cross-on | on | cross-on | cross | cross-on | cross-on | cross-on | on | on | cross | cross-on | cross-on |
High Tide | 8:23PM4.91m | 9:02AM4.96m | 9:21PM5.29m | 9:53AM5.26m | 10:08PM5.63m | 10:36AM5.47m | 10:49PM5.85m | 11:14AM5.59m | 11:28PM5.95m | 11:50AM5.61m | 00:04AM5.91m | 12:25PM5.56m | 00:40AM5.77m | ||||||||
Low Tide | 1:57PM1.96m | 2:38AM1.44m | 3:00PM1.61m | 3:33AM1.02m | 3:50PM1.24m | 4:19AM0.68m | 4:32PM0.95m | 5:00AM0.47m | 5:11PM0.75m | 5:39AM0.42m | 5:49PM0.68m | 6:16AM0.50m | 6:26PM0.74m | ||||||||
 |  |  |  | |  | | | | | |  | | |  |  | | | | | | |
 | 6:37 | — | — | 6:39 | — | — | 6:39 | — | — | 6:41 | — | — | 6:43 | — | — | 6:45 | — | — | 6:47 | — | — |
 | — | 7:53 | — | — | 7:52 | — | — | 7:50 | — | — | 7:46 | — | — | 7:45 | — | — | 7:42 | — | — | 7:39 | — |
mm | — | 2 | 2 | — | — | — | — | — | — | — | — | 2 | — | — | — | 2 | 5 | 1 | — | — | — |
Temp °C | 15 | 16 | 14 | 14 | 16 | 14 | 13 | 14 | 15 | 16 | 16 | 17 | 14 | 15 | 14 | 14 | 15 | 17 | 16 | 16 | 15 |
Feels °C | 11 | 10 | 10 | 6 | 8 | 6 | 8 | 11 | 10 | 9 | 9 | 13 | 10 | 13 | 11 | 6 | 7 | 13 | 13 | 14 | 12 |
Swell 1 Height (m) Direction Period (s) | SW 14 | — | SW 7 | SW 12 | SW 11 | SW 6 | SW 7 | N 5 | SSW 7 | — | — | SW 6 | SW 6 | SW 6 | — | — | — | SW 7 | SW 7 | NNW 5 | — |
| kJ | 33 | — | 163 | 5 | 5 | 5 | 19 | 18 | 5 | — | — | 120 | 33 | 19 | — | — | — | 173 | 44 | 4 | — |
Swell 2 Height (m) Direction Period (s) | — | — | SW 12 | SW 11 | SW 10 | SW 10 | — | W 4 | N 4 | — | — | — | — | — | — | — | — | — | NW 4 | — | — |
| kJ | — | — | 6 | 5 | 4 | 4 | — | 2 | 1 | — | — | — | — | — | — | — | — | — | 11 | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | SW 7 | — | — | — | — | — | — | — | — | — | — | — | S 13 | — |
| kJ | — | — | — | — | — | — | — | 14 | — | — | — | — | — | — | — | — | — | — | — | 3 | — |
Wind waves Height (m) Direction Period (s) | WSW 4 | SW 5 | NW 4 | W 5 | WNW 5 | NW 6 | NNW 6 | — | SW 4 | SW 4 | SSW 6 | — | NW 4 | NW 4 | SW 3 | SSW 5 | SSW 6 | — | — | SSW 6 | SSW 5 |
| kJ | 34 | 94 | 9 | 81 | 105 | 198 | 77 | — | 11 | 40 | 176 | — | 24 | 7 | 12 | 116 | 406 | — | — | 35 | 46 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 51 | 326 | 219 | 179 | 1094 | 346 | 187 | 250 | 194 | 280 | 280 | 167 | 179 | 195 | 179 | 238 | 246 | 251 | 298 | 275 | 186 |
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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