Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 16 Aug 2026:
- Most powerful swell: Wednesday 19 Aug, 7PM (local time) - 4.5ft (1.4m), 5s period, SW swell with 102 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 1.4m 5s and forecast to arrive on Wednesday (Aug 19) at 7PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 5s period and expected on Thursday (Aug 20) at 4AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 7PM (Wed 19th Aug) | 4.5ft (1.4m) 5s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright, let’s get this straight. I’ve looked at the charts for the next couple of weeks, and I’ve got to be honest with you, mate – it’s a brutal outlook for Trearddur Bay. We’re looking at a proper dry spell.
For the first ten days or so, from Sunday the 16th of August right through to the end of the month, the swell is just not there. The odd 1ft to 1ft bump shows up here and there, but with a period of 4 to 6 seconds, it’s just wind slop. On top of that, the wind is mostly onshore or cross-onshore, so it’s choppy and messy. There’s a stretch from the 17th to the 24th where the waves are basically non-existent, with a few 0.3ft pulses from the SW that have a good period (14-15 seconds), but they’re just too weak to do anything with. The combined energy hardly breaks 20 (8-13) during that whole period, so it’s a total write-off. The wind does turn offshore and clean from the 22nd onward, but again, there’s nothing to push.
The first real glimmer of hope doesn’t show up until Thursday the 27th of August. On the afternoon of the 27th, we’ve got a 6ft swell from the SSW with a 6 second period. The combined energy hits 204, so there’s some moderate power behind it. The wind is light and cross-offshore from the north, so it’ll be clean. But that 6ft is getting a bit big for a beginner spot, and the short period means it’ll be a bit fat and maybe a bit too straight for the bay. Still, it’s the only wave on offer in the whole 16 days that’s even surfable, so it’s the standout by default. It’s not a classic, but it’s something.
After that, the 28th and 29th of August see the swell drop back down, and the wind turns onshore again, killing it. The 30th of August has a similar story: a 5ft swell from the SW on the afternoon, but with light onshore wind, it’s messy.
The 27th afternoon is the best you’re going to get. It’s not going to be world-class, but it’s the only window where you can actually paddle out. Get on it if you’re desperate.
Rusty.
Short Range ForecastLight rain (total 4mm), mostly falling on Mon night. Very mild (max 17°C on Mon night, min 13°C on Sat night). Winds increasing (calm on Sat night, fresh winds from the S by Mon night). | Days 4-6 Weather SummaryLight rain (total 2mm), mostly falling on Wed afternoon. Very mild (max 17°C on Tue night, min 13°C on Thu night). Winds decreasing (fresh winds from the W on Wed night, light winds from the NW by Thu afternoon). | ||||||||||||||||||||
Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | |||||||||||||||
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) | — | — | SSW 3 | NW 3 | SW 5 | SW 4 | WNW 5 | W 4 | WNW 4 | W 4 | SW 5 | NW 5 | SW 6 | SW 6 | SW 14 | SW 14 | SW 13 | SW 13 | SW 15 | SW 15 | SW 15 |
Wave Graph  | |||||||||||||||||||||
 kJ | 0 | 0 | 4 | 2 | 3 | 25 | 37 | 24 | 20 | 38 | 92 | 41 | 12 | 8 | 8 | 7 | 7 | 7 | 8 | 8 | 8 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | cross-on | cross-on | cross-on | on | cross-on | on | cross-on | on | on | cross-on | cross | cross | cross-off | cross | cross-off | cross-off | cross-off | off | off |
High Tide | 1:35PM5.37m | 1:49AM5.63m | 2:12PM5.16m | 2:28AM5.33m | 2:51PM4.93m | 3:07AM4.98m | 3:32PM4.68m | 3:52AM4.62m | 4:23PM4.44m | 4:52AM4.29m | 5:32PM4.26m | 6:23AM4.10m | 7:07PM4.27m | ||||||||
Low Tide | 7:25AM0.53m | 7:34PM0.87m | 8:05AM0.82m | 8:13PM1.14m | 8:44AM1.19m | 8:54PM1.47m | 9:26AM1.59m | 9:39PM1.83m | 10:14AM1.98m | 10:37PM2.18m | 11:17AM2.31m | 11:58PM2.41m | 12:45PM2.45m | 1:37AM2.37m | |||||||
 |  |  |  | |  | | |  | | | | |  |  | | | | | | | |
 | 5:58 | — | — | 6:01 | — | — | 6:01 | — | — | 6:03 | — | — | 6:05 | — | — | 6:07 | — | — | 6:09 | — | — |
 | — | 8:45 | — | — | 8:43 | — | — | 8:40 | — | — | 8:37 | — | — | 8:36 | — | — | 8:34 | — | — | 8:31 | — |
mm | — | 1 | — | — | — | 3 | — | — | — | — | 1 | 1 | — | — | — | — | — | 2 | — | — | — |
Temp °C | 14 | 15 | 16 | 15 | 15 | 17 | 16 | 17 | 17 | 15 | 17 | 16 | 15 | 16 | 15 | 13 | 14 | 14 | 15 | 16 | 15 |
Feels °C | 13 | 13 | 16 | 13 | 14 | 15 | 12 | 14 | 15 | 9 | 11 | 10 | 12 | 14 | 12 | 10 | 10 | 13 | 9 | 10 | 11 |
Swell 1 Height (m) Direction Period (s) | — | — | — | SW 4 | SW 5 | — | SW 5 | — | SW 5 | SW 16 | WNW 5 | SW 6 | SW 6 | SW 6 | SW 5 | NNW 5 | NNW 4 | SW 13 | NNW 4 | SW 15 | SW 15 |
| kJ | — | — | — | 2 | 3 | — | 22 | — | 1 | 10 | 3 | 38 | 12 | 5 | 1 | 28 | 6 | 7 | 3 | 8 | 8 |
Swell 2 Height (m) Direction Period (s) | — | — | — | — | NW 3 | — | — | S 16 | — | — | — | SW 16 | SW 15 | SW 14 | SW 14 | SW 5 | W 3 | — | SW 15 | — | S 12 |
| kJ | — | — | — | — | 2 | — | — | 5 | — | — | — | 10 | 8 | 8 | 8 | 1 | 2 | — | 8 | — | 3 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | SW 14 | SW 13 | — | — | S 12 | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 7 | 7 | — | — | 3 | — |
Wind waves Height (m) Direction Period (s) | — | — | SSW 3 | NW 3 | NW 3 | SW 4 | WNW 5 | W 4 | WNW 4 | W 4 | SW 5 | NW 5 | NNW 5 | NW 4 | NNW 5 | — | WNW 4 | NNE 4 | — | NNW 4 | NNW 4 |
| kJ | — | — | 4 | 2 | 3 | 25 | 37 | 24 | 20 | 38 | 92 | 41 | 48 | 19 | 58 | — | 2 | 10 | — | 4 | 4 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 246 | 285 | 210 | 249 | 249 | 567 | 326 | 376 | 251 | 246 | 293 | 235 | 235 | 332 | 179 | 249 | 249 | 219 | 284 | 284 | 163 |
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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