Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 12 Aug 2026:
- Most powerful swell: Wednesday 19 Aug, 10AM (local time) - 5.5ft (1.7m), 6s period, WNW swell with 173 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 1.7m 6s and forecast to arrive on Wednesday (Aug 19) at 10AM. 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 5s period and expected on Sunday (Aug 16) at 4AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 10AM (Wed 19th Aug) | 5.5ft (1.7m) 6s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Right then, let’s talk about Trearddur Bay (Holy Island).
Honestly, I’m looking at the whole 16-day window and it’s pretty flat and grim for a lot of it. There’s no good surf on offer right now and things stay that way for a good long stretch. From Wednesday August 12th right through until the middle of the following week, it’s all tiny dribble – at best 1 feet and with short, weak periods. The combined swell energy rarely breaks double digits, often sitting at a pathetic 1 to 13 (weak energy). The wind’s cross-on or onshore most of that time too, so you’d be scratching around in choppy, messy conditions. There’s a big gap of poor to zero surf for days on end.
Now, the one thing that catches my eye – and I mean *the* standout – is Thursday August 20th. Early that morning we get a jump to 6 feet swell from the NW, period 6 seconds, with combined energy hitting 264 (moderate wave energy). That’s the most energy we see across the whole outlook. The wind is offshore from the NE at 16 mph, so Trearddur Bay should be clean and lined up. That’s the session to aim for, but keep in mind the period is short – only 6 seconds – so waves will be a bit crumbly and soft, not that deep power.
Friday August 19th morning also shows some pulse: 6 feet from the WNW, period 6 seconds, energy 183. The wind is light onshore though (SW 9 mph), so it’ll be a bit lumpy. Thursday afternoon the 20th drops to 4 feet but stays clean with cross-offshore wind.
After that, it’s back to tiny leftovers. Wave heights drop to 0.3 feet from the 21st right through to the 23rd, with long periods of 13-14 seconds, but absolutely no height – those are just ghost swells. The combined energy is below 20 (weak).
By Monday August 24th morning we get a little bump: 4 feet from the SSW, period 7 seconds, energy 128 (moderate). Clean with cross-offshore NNW wind at 12 mph. That’s a possible morning surf, but nothing like the Thursday 20th.
For the rest of the second week it’s mostly small and weak – 0.3 feet to 2 feet, with onshore or cross winds. Not worth getting excited about.
Trearddur Bay is a beginner-friendly, fairly exposed spot, but it’s inconsistent and rarely fires. The best of a poor bunch is clearly Thursday August 20th morning.
Rusty.
Short Range ForecastSome drizzle, heaviest during Fri morning. Warm (max 26°C on Wed afternoon, min 14°C on Fri night). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 15mm), heaviest on Mon morning. Very mild (max 18°C on Mon afternoon, min 13°C on Sat night). Mainly strong winds. | ||||||||||||||||||||
Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | |||||||||||||||
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 12 | SW 12 | SW 10 | SW 11 | SW 11 | SW 5 | NW 4 | NW 4 | SSW 6 | SW 6 | SW 6 | SW 6 | NNW 5 | W 7 | W 7 | SSW 2 | S 4 | SSW 5 | SW 6 | SSW 4 | SW 6 |
Wave Graph  | |||||||||||||||||||||
 kJ | 6 | 6 | 4 | 5 | 4 | 26 | 7 | 5 | 3 | 1 | 2 | 1 | 0 | 1 | 1 | 1 | 27 | 20 | 10 | 26 | 46 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | on | on | cross-on | cross-on | cross-off | cross-off | cross-off | cross | cross-off | cross-off | cross-off | cross-on | cross-on | cross-on | cross | cross-on | on | on |
High Tide | 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 | 2:51PM4.93m | 3:07AM4.98m | |||||||
Low Tide | 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 | 8:44AM1.19m | 8:54PM1.47m | ||||||||
 |  |  | | | |  | |  | |  | | | |  |  | |  | | |  | |
 | 5:52 | — | — | 5:54 | — | — | 5:54 | — | — | 5:56 | — | — | 5:58 | — | — | 6:01 | — | — | 6:01 | — | — |
 | — | 8:52 | — | — | 8:51 | — | — | 8:49 | — | — | 8:46 | — | — | 8:45 | — | — | 8:43 | — | — | 8:40 | — |
mm | — | — | — | — | — | — | 1 | — | — | — | — | — | — | — | 2 | 12 | — | 1 | — | — | 15 |
Temp °C | 23 | 26 | 25 | 22 | 22 | 19 | 17 | 17 | 16 | 15 | 15 | 15 | 14 | 16 | 15 | 16 | 18 | 17 | 16 | 18 | 19 |
Feels °C | 20 | 24 | 24 | 21 | 22 | 16 | 16 | 15 | 13 | 10 | 11 | 11 | 10 | 14 | 14 | 13 | 17 | 12 | 12 | 16 | 17 |
Swell 1 Height (m) Direction Period (s) | SW 12 | SSW 3 | SW 10 | SW 8 | SW 8 | SW 5 | SW 4 | NW 4 | SSW 6 | SW 6 | SW 6 | SW 6 | — | W 7 | NNW 4 | N 4 | — | SSW 5 | SW 6 | — | SW 6 |
| kJ | 6 | 2 | 4 | 3 | 2 | 26 | 7 | 3 | 3 | 1 | 2 | 1 | — | 1 | 3 | 1 | — | 20 | 10 | — | 46 |
Swell 2 Height (m) Direction Period (s) | S 6 | SW 12 | — | SW 5 | SW 11 | S 11 | — | SW 5 | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | 1 | 6 | — | 1 | 4 | 2 | — | 3 | — | — | — | — | — | — | — | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | W 10 | SW 6 | — | SW 11 | S 11 | — | — | N 4 | — | — | — | — | — | — | W 7 | — | — | — | — | — | — |
| kJ | 2 | 1 | — | 5 | 2 | — | — | 2 | — | — | — | — | — | — | 1 | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | SSW 3 | — | SSW 5 | SW 3 | SSW 2 | SW 5 | NW 4 | NW 4 | N 4 | NNW 4 | NNW 4 | N 4 | NNW 5 | NNW 5 | — | SSW 2 | S 4 | — | — | SSW 4 | WNW 4 |
| kJ | 3 | — | 3 | 1 | 1 | 26 | 6 | 5 | 5 | 21 | 13 | 18 | 31 | 17 | — | 1 | 27 | — | — | 26 | 19 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 235 | 163 | 163 | 179 | 249 | 192 | 195 | 566 | 323 | 620 | 604 | 278 | 278 | 285 | 287 | 292 | 312 | 179 | 302 | 292 | 114 |
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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