Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 29 Aug 2026:
- Most powerful swell: Wednesday 2 Sep, 7PM (local time) - 8ft (2.4m), 7s period, SW swell with 566 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 2.4m 7s and forecast to arrive on Wednesday (Sep 02) 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 1.2m 5s period and expected on Saturday (Sep 05) at 1AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 7PM (Wed 2nd Sep) | 8ft (2.4m) 7s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Right then, let's have a look at what we've got for Trearddur Bay on Holy Island. I'll be straight with ya – this forecast is a rough one for us surfers. Honestly, looking at the whole 16-day window, there's a stack of "poor surf conditions" reports. The wave energy is mostly weak, with readings like 44, 26, even down to single digits on some days. The water's sitting at 64°, which is a touch warmer than what we'd normally expect for this time of year.
For the first week, from Saturday the 29th right through to the 7th of September, it's a real struggle. We get tiny swell, mostly around 2 ft to 4 ft, mixed with strong onshore or cross-shore winds that are just wrecking any chance of a clean wave. The wind is gusting from 19 mph up to 25 mph from the S and SSW, making it lumpy and messy. There's a bit more size on the 31st of August with a 5 ft NW swell and moderate energy (218), but that NW wind is howling at 25 mph, creating a messy cross-chop. Later in the week, around the 2nd and 6th of September, we see the swell picking up to 6 ft and 8 ft, but again, it's accompanied by strong onshore winds from the SSW and SW. That's just ugly surf. The whole week is pretty much a write-off.
Then we hit a dry spell. The 7th of September has a tiny 2 ft bump, and the 8th and 9th are flat with next to no energy (energy readings of 8 and 7). You're looking at about two days of nothing worthwhile.
Now, things get interesting way out at the end, on Thursday the 10th of September. The swell jumps up to a solid 12 ft from the SW, with a period of 8 seconds. The wave energy is huge—we're talking 1,961 and 2,039. But here's the kicker, it's predicted to be too big for Trearddur Bay. The morning on the 10th has light cross-shore winds from the SSE at 6 mph, so conditions might be glassy, but the sheer size of that swell is going to close out the bay and be dangerous. That one is for absolute experts only, and even then, it's a heavy paddle.
After that, it drops back down. The 11th and 12th of September see the swell shrink to 4 ft and 3 ft, but we're back to fresh, lumpy cross-onshore winds.
So, to sum it up: the best of a bad bunch is that far-off date of Thursday the 10th of September. It's the only time we get any serious power and groundswell potential, but you have to be an absolute charger to even think about it, and it's still a big, unpredictable cleanup set. For the rest of us, this forecast is a solid two weeks of disappointment.
Rusty.
Short Range ForecastLight rain (total 6mm), mostly falling on Sat afternoon. Very mild (max 17°C on Sun morning, min 14°C on Mon morning). Winds increasing (light winds from the WSW on Sat night, strong winds from the WNW by Mon morning). | Days 5-7 Weather SummaryLight rain (total 7mm), mostly falling on Wed morning. Very mild (max 17°C on Tue afternoon, min 13°C on Thu night). Mainly strong winds. | |||||||||||||||||||
Sat 29 | Sunday 30 | Monday 31 | Tuesday 1 | Wednesday 2 | Thursday 3 | Friday 4 | ||||||||||||||
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) | SSW 6 | SSW 8 | SSW 8 | SSW 5 | SW 8 | WNW 6 | NW 5 | SSW 7 | SW 4 | SW 5 | SW 5 | SSW 7 | SW 7 | SW 7 | SW 6 | SW 6 | WSW 7 | W 6 | W 5 | SW 5 |
Wave Graph | ||||||||||||||||||||
29 | 126 | 92 | 72 | 110 | 143 | 51 | 21 | 29 | 53 | 79 | 444 | 495 | 301 | 171 | 190 | 517 | 366 | 121 | 12 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | on | cross-on | cross-on | cross-on | cross | cross-on | cross-on | on | on | on | cross-on | on | on | on | cross-on | cross-on | cross-on | cross-on | on |
High Tide | 00:07AM5.72m | 12:28PM5.40m | 00:40AM5.74m | 1:01PM5.41m | 1:15AM5.69m | 1:36PM5.36m | 1:53AM5.56m | 2:15PM5.23m | 2:36AM5.34m | 3:01PM5.01m | 3:30AM5.02m | 3:59PM4.75m | ||||||||
Low Tide | 5:55PM0.94m | 6:16AM0.70m | 6:28PM0.87m | 6:50AM0.69m | 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 | |||||||
— | — | 6:22 | — | — | 6:24 | — | — | 6:26 | — | — | 6:28 | — | — | 6:30 | — | — | 6:31 | — | — | |
8:15 | — | — | 8:13 | — | — | 8:10 | — | — | 8:08 | — | — | 8:06 | — | — | 8:04 | — | — | 8:01 | — | |
mm | 2 | — | 2 | 2 | — | — | — | — | — | 1 | 3 | 3 | — | — | — | — | — | — | — | — |
Temp °C | 16 | 15 | 17 | 16 | 16 | 14 | 16 | 16 | 16 | 17 | 17 | 17 | 17 | 17 | 16 | 17 | 15 | 15 | 17 | 17 |
Feels °C | 14 | 14 | 13 | 11 | 13 | 6 | 13 | 13 | 12 | 12 | 13 | 11 | 11 | 12 | 9 | 10 | 7 | 9 | 13 | 12 |
Swell 1 Height (m) Direction Period (s) | SSW 6 | SSW 8 | — | SW 8 | SW 8 | SW 8 | SW 8 | SSW 7 | — | WNW 4 | — | — | — | SW 15 | SW 14 | SW 14 | — | — | NNW 6 | SW 5 |
29 | 126 | — | 11 | 110 | 64 | 50 | 21 | — | 1 | — | — | — | 9 | 8 | 8 | — | — | 20 | 12 | |
Swell 2 Height (m) Direction Period (s) | — | NW 3 | — | — | — | — | — | NNW 5 | — | — | — | — | — | — | — | — | — | — | SW 14 | SW 6 |
— | 2 | — | — | — | — | — | 5 | — | — | — | — | — | — | — | — | — | — | 8 | 10 | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | SW 14 |
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 8 | |
Wind waves Height (m) Direction Period (s) | — | — | SSW 8 | SSW 5 | — | WNW 6 | NW 5 | W 3 | SW 4 | SW 5 | SW 5 | SSW 7 | SW 7 | SW 7 | SW 6 | SW 6 | WSW 7 | W 6 | W 5 | NW 5 |
— | — | 92 | 72 | — | 143 | 51 | 5 | 29 | 53 | 79 | 444 | 495 | 301 | 171 | 190 | 517 | 366 | 121 | 74 | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 208 | 192 | 51 | 255 | 223 | 51 | 305 | 51 | 179 | 305 | 251 | 246 | 246 | 503 | 284 | 350 | 548 | 548 | 556 | 51 |
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.











