Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 11 Aug 2026:
- Most powerful swell: Tuesday 18 Aug, 4PM (local time) - 3ft (0.9m), 5s period, SW swell with 31 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 0.9m 5s and forecast to arrive on Tuesday (Aug 18) at 4PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 4s period and expected on Saturday (Aug 15) at 4AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 4PM (Tue 18th Aug) | 3ft (0.9m) 5s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright, let's have a look at what's on the table.
To be honest, mate, the next couple of weeks are looking pretty grim. For the most part, we're looking at flat to tiny, weak swell and onshore or cross-off winds that just won’t give us anything decent. There’s a long dry spell on the cards.
Looking at Trearddur Bay (Holy Island), the water is a touch warmer than normal for this time of year, sitting at about 63°, so it's not a bad time to be in the water, but you won’t be doing much riding.
The first bit of hope shows up on the 24th of August, Monday morning. A moderate offshore breeze from the NE at 16 mph should clean things up, and we’ll see a 5 ft SSW swell roll in. The combined energy hits 155 (moderate), so there's enough push. It’s a bit of a wait, but that’s the first real chance of a wave.
The true standout, what I’d be waiting for, arrives on Wednesday the 26th of August. We’ve got glassy conditions, practically no wind at all, which is dead-set perfect. That SW swell will be pushing 7 ft with a combined energy of 385 (strong). That’s not for beginners – that’s a decent-sized, powerful groundswell, and with the period sitting at 7 seconds, it won’t be too fat, but still a meaty wave. This is your best bet of the whole outlook, but remember it’s a week and a half away, so keep an eye on it.
Outside of that, the rest of the period is a write-off. There’s nothing else worth paddling out for.
Rusty.
Short Range ForecastSome drizzle, heaviest during Fri morning. Warm (max 25°C on Wed afternoon, min 16°C on Fri morning). Wind will be generally light. | Days 5-7 Weather SummaryMostly dry. Very mild (max 18°C on Fri afternoon, min 13°C on Sat morning). Wind will be generally light. | |||||||||||||||||||
Tue 11 | Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | ||||||||||||||
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) | S 3 | S 11 | SW 12 | SW 12 | SW 10 | SW 10 | SW 11 | SW 4 | SSW 5 | SW 5 | SW 6 | SW 6 | SW 6 | SW 7 | W 7 | NNW 4 | N 4 | NNW 4 | NNW 3 | — |
Wave Graph  | ||||||||||||||||||||
 kJ | 1 | 2 | 6 | 6 | 4 | 4 | 4 | 9 | 9 | 4 | 1 | 1 | 1 | 2 | 1 | 0 | 0 | 0 | 0 | 0 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | cross | cross-on | cross-on | cross-on | on | cross-on | glassy | cross | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross | off | cross-off | cross-off | off |
High Tide | 10:21PM5.51m | 10:50AM5.42m | 11:07PM5.78m | 11:35AM5.56m | 11:49PM5.94m | 12:16PM5.58m | 00:30AM5.96m | 12:56PM5.52m | 1:10AM5.85m | 1:35PM5.37m | 1:49AM5.63m | 2:12PM5.16m | 2:28AM5.33m | |||||||
Low Tide | 4:01PM1.21m | 4:33AM0.72m | 4:48PM0.94m | 5:19AM0.45m | 5:32PM0.74m | 6:02AM0.32m | 6:14PM0.67m | 6:44AM0.35m | 6:54PM0.71m | 7:25AM0.53m | 7:34PM0.87m | 8:05AM0.82m | 8:13PM1.14m | |||||||
 |  | |  | | | |  |  | | | | | | |  |  | | | | |
 | — | — | 5:52 | — | — | 5:54 | — | — | 5:54 | — | — | 5:56 | — | — | 5:58 | — | — | 6:01 | — | — |
 | 8:54 | — | — | 8:52 | — | — | 8:51 | — | — | 8:49 | — | — | 8:46 | — | — | 8:45 | — | — | 8:43 | — |
mm | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 20 | 21 | 22 | 25 | 24 | 21 | 22 | 21 | 18 | 18 | 17 | 14 | 15 | 15 | 14 | 15 | 15 | 16 | 18 | 17 |
Feels °C | 18 | 21 | 19 | 23 | 23 | 20 | 23 | 22 | 18 | 16 | 14 | 10 | 11 | 12 | 12 | 13 | 13 | 13 | 16 | 15 |
Swell 1 Height (m) Direction Period (s) | SW 6 | — | SW 12 | SSW 3 | SW 5 | SW 8 | SW 8 | SW 4 | SSW 5 | SW 5 | SW 6 | SW 6 | SW 6 | — | W 7 | NNW 4 | — | NNW 4 | — | — |
| kJ | 1 | — | 6 | 1 | 1 | 3 | 2 | 9 | 9 | 4 | 1 | 1 | 1 | — | 1 | 6 | — | 2 | — | — |
Swell 2 Height (m) Direction Period (s) | — | SW 6 | SW 6 | SW 12 | SW 10 | SW 5 | SW 11 | S 11 | — | — | — | — | — | SW 7 | — | — | — | — | — | — |
| kJ | — | 1 | 1 | 6 | 4 | 1 | 4 | 2 | — | — | — | — | — | 2 | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | S 11 | W 10 | SW 6 | — | SW 10 | S 11 | SW 11 | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | 2 | 2 | 1 | — | 4 | 2 | 5 | — | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | S 3 | — | SSW 3 | — | — | — | — | SSE 2 | WNW 3 | NW 4 | N 4 | NNW 5 | NNW 4 | N 4 | N 4 | — | N 4 | — | NNW 3 | — |
| kJ | 1 | — | 3 | — | — | — | — | 1 | 2 | 6 | 18 | 25 | 15 | 6 | 9 | — | 1 | — | 1 | — |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 306 | 163 | 179 | 182 | 155 | 179 | 288 | 192 | 195 | 587 | 326 | 318 | 510 | 251 | 249 | 285 | 285 | 286 | 288 | 184 |
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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