Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 3 Sep 2026:
- Most powerful swell: Tuesday 8 Sep, 7AM (local time) - 7ft (2.1m), 6s period, WSW swell with 310 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 2.1m 6s and forecast to arrive on Tuesday (Sep 08) at 7AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 5s period and expected on Saturday (Sep 05) at 1PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 7AM (Tue 8th Sep) | 7ft (2.1m) 6s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Imperial
Alright, let’s be real. This is a tough stretch. Looking at Trearddur Bay (Holy Island), there’s nothing worth paddling out for in the next 16 days. It’s a long, dry gap of poor conditions.
We kick off on Thursday, September 3rd, with a 4ft swell from the SW, period of 7 seconds, but a 16 mph onshore wind is just killing it. Water temp is 62°, a touch warmer than normal, but the surf is junk. The combined energy is 155 (moderate), but it doesn’t matter with that wind.
Friday the 4th is worse. The swell hits 6ft from the WSW, period drops to a terrible 5 seconds, and we’ve got a strong 25 mph cross-onshore wind. It’s a complete mess. The energy is 163, but it’s all wind chop.
The whole first week is the same story. Saturday the 5th, the swell drops to 2ft. Sunday the 6th brings it back up to 5ft, but it’s lumpy and cross-onshore again. Day after day, it’s onshore or cross-onshore winds, short-period swell, and the word is always “poor.” Energy values sit between 100 and 177, but it’s all for nothing.
There’s a tiny glimmer on Saturday the 12th, in the morning. We get a 5ft swell from the NW with a 6 mph easterly cross-offshore breeze, and the ocean goes clean. The energy is 198 (moderate). But the wave comment says “surfable waves but very ordinary conditions,” and it’s only a 1 out of 10. It’s not enough, and by the afternoon the wind is back onshore and the swell is gone.
Sunday the 13th morning brings the biggest swell of the whole run at 7ft from the SSW, with a period of 6 seconds. The energy jumps to 320 (strong). But it’s a cross-shore wind, and it’s marginal. The afternoon swell hits 8ft with energy at 486 (strong), but again, it’s cross-shore and messy. At that size with a short period, it’s only for the experienced, and even then it’s not clean.
After that, it all fades to nothing. From the 14th onward, the swell drops off, energy values fall to single digits. By the 16th, there’s no swell at all. Just a few weak, onshore days to finish.
I hate to say it, but Trearddur Bay is a write-off. When a spot is as inconsistent as this one, a blank run like this is more normal for the area. We just gotta sit this one out and hope the forecasts change. Don’t hold your breath.
Rusty.
Short Range ForecastModerate rain (total 17mm), heaviest on Thu night. Very mild (max 17°C on Thu afternoon, min 13°C on Fri night). Mainly fresh winds. | Days 5-7 Weather SummaryModerate rain (total 11mm), heaviest on Mon night. Warm (max 20°C on Sun afternoon, min 13°C on Mon night). Winds increasing (moderate winds from the W on Mon morning, strong winds from the W by Tue night). | |||||||||||||||||||
Thu 3 | Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | ||||||||||||||
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 6 | SW 7 | WSW 5 | SW 5 | W 5 | W 5 | SW 6 | SSW 4 | SSW 5 | SSW 5 | SSW 6 | WSW 5 | SW 5 | WSW 6 | W 6 | WSW 6 | WSW 6 | WSW 6 | SW 6 | SW 7 |
Wave Graph  | ||||||||||||||||||||
 kJ | 123 | 178 | 168 | 119 | 115 | 49 | 26 | 42 | 44 | 64 | 202 | 59 | 103 | 253 | 298 | 246 | 240 | 193 | 76 | 178 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | cross-on | on | cross-on | cross-on | on | cross-on | cross-on | cross-on | cross-on | cross-on | on | on | cross-on | cross-on | cross-on | cross-on | cross-on | on |
High Tide | 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 | ||||||||
 |  |  |  |  | | |  |  |  | | | | | | |  | | |  | |
 | — | — | 6:31 | — | — | 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 | 1 | 13 | — | — | — | — | — | 2 | 1 | — | 1 | — | — | 10 | — | — | — | — | — | 6 |
Temp °C | 17 | 15 | 15 | 17 | 15 | 14 | 14 | 15 | 17 | 20 | 17 | 15 | 15 | 14 | 14 | 15 | 14 | 15 | 16 | 14 |
Feels °C | 12 | 13 | 8 | 11 | 8 | 11 | 10 | 9 | 10 | 15 | 12 | 11 | 9 | 8 | 6 | 7 | 5 | 8 | 11 | 10 |
Swell 1 Height (m) Direction Period (s) | — | SW 7 | SW 14 | SW 14 | SW 14 | SW 14 | WNW 4 | SW 13 | SW 13 | SW 13 | SW 12 | WSW 14 | — | — | — | — | — | — | NW 5 | — |
| kJ | — | 178 | 8 | 8 | 8 | 7 | 3 | 7 | 7 | 6 | 6 | 20 | — | — | — | — | — | — | 7 | — |
Swell 2 Height (m) Direction Period (s) | — | NW 4 | — | SW 14 | — | SW 7 | NNW 5 | — | — | — | — | — | — | — | — | — | — | — | NNW 6 | — |
| kJ | — | 3 | — | 8 | — | 7 | 5 | — | — | — | — | — | — | — | — | — | — | — | 3 | — |
Swell 3 Height (m) Direction Period (s) | — | SW 14 | — | — | — | SW 14 | SW 13 | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | 8 | — | — | — | 7 | 7 | — | — | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | SW 6 | SW 6 | WSW 5 | SW 5 | W 5 | W 5 | SW 6 | SSW 4 | SSW 5 | SSW 5 | SSW 6 | WSW 5 | SW 5 | WSW 6 | W 6 | WSW 6 | WSW 6 | WSW 6 | SW 6 | SW 7 |
| kJ | 123 | 167 | 168 | 119 | 115 | 49 | 26 | 42 | 44 | 64 | 202 | 59 | 103 | 253 | 298 | 246 | 240 | 193 | 76 | 178 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 293 | 167 | 346 | 548 | 179 | 51 | 236 | 186 | 238 | 189 | 280 | 174 | 251 | 251 | 597 | 548 | 556 | 376 | 251 | 246 |
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.
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