Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 17 Aug 2026:
- Most powerful swell: Wednesday 19 Aug, 7PM (local time) - 4.5ft (1.4m), 6s period, SW swell with 138 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 6s and forecast to arrive on Wednesday (Aug 19) 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 1.0m 4s period and expected on Thursday (Aug 20) at 4PM.
| 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) 6s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Hey folks, Rusty here. Let's be straight with you: the next couple of weeks are looking pretty grim for a paddle around Trearddur Bay (Holy Island). We're in for a long, quiet stretch.
Looking at the whole 16-day window, there's just no decent surf on offer. The first real chance of anything rideable doesn't show up until late in the period, but even then it's rough.
From now until about the 27th of August, it's mostly tiny, weak stuff mixed with onshore winds. The swell energy is in the doldrums, mostly reading single digits or low double-digits. You'll see a bit of a spike on the 19th with waves hitting 4ft, but the wind is howling on it at 22 mph from the SSW, making it messy. Not worth a second look. A few days around the 20th and 21st have clean conditions with light offshore or cross-off winds, but the swell is pathetic at 0.7ft to 2ft. You'd need a stand-up paddleboard, not a surfboard.
Then there's a real drought from the 22nd through the 25th of August. The swell drops to just 0.3ft with a very long period of 14-15 seconds, but that energy is practically non-existent. It's a ghost town.
We finally see a pulse of energy on the 28th of August. The Thursday morning sees swell bumping up to 5ft from the WNW with a period of 6 seconds, and combined wave energy climbing to a strong 205. Problem is, the wind is a fresh cross-onshore at 22 mph, making it lumpy and choppy. The afternoon isn't much better. With waves at that size and period, it's more suited for the experts, but the wind is going to ruin any chance of a clean face. Honestly, that setup looks more interesting for kite surfing than a paddle session.
The end of the month into the 31st of August stays onshore and messy with more wind and choppy conditions. There's simply no standout day. The only positive is that the water temperature is 64°, which is a touch warmer than normal for this time of year, so you won't freeze waiting for a set that never comes.
Sorry, folks, but that's the long and short of it. A blank run like this is pretty normal for the area when the patterns shut down. Keep an eye on it, though – forecasts can change.
Rusty
Short Range ForecastLight rain (total 2mm), mostly falling on Mon night. Very mild (max 18°C on Tue afternoon, min 14°C on Tue night). Winds increasing (light winds from the W on Sun night, fresh winds from the SSW by Mon night). | Days 5-7 Weather SummaryLight rain (total 6mm), mostly falling on Wed afternoon. Very mild (max 16°C on Wed afternoon, min 13°C on Thu night). Winds decreasing (fresh winds from the SSW on Wed afternoon, light winds from the NNE by Fri morning). | |||||||||||||||||||
Sun 16 | Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | ||||||||||||||
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 2 | SW 4 | SW 5 | SW 5 | SW 4 | WSW 4 | SW 6 | WSW 4 | WSW 5 | SW 5 | SW 6 | SW 6 | SW 6 | SW 14 | W 3 | W 3 | SW 13 | SW 15 | SW 15 | SW 15 |
Wave Graph  | ||||||||||||||||||||
 kJ | 1 | 5 | 6 | 4 | 23 | 24 | 16 | 26 | 69 | 100 | 66 | 25 | 13 | 8 | 1 | 1 | 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 | on | cross-on | on | cross-on | on | on | cross-on | cross-off | cross-off | cross-off | off | cross-off | cross-off | cross-off | cross-off | cross-off |
High Tide | 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 | 7:34PM0.87m | 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 | |||||||
 |  | | |  |  | |  | |  |  | | | | |  | | | |  | |
 | — | — | 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 | — | — | — | — | 2 | — | — | — | — | 1 | 2 | 2 | — | 1 | — | — | — | — | — | — |
Temp °C | 15 | 16 | 15 | 16 | 17 | 16 | 18 | 18 | 15 | 16 | 16 | 15 | 15 | 14 | 14 | 15 | 13 | 13 | 14 | 14 |
Feels °C | 11 | 16 | 14 | 13 | 14 | 13 | 16 | 15 | 9 | 9 | 11 | 8 | 10 | 10 | 11 | 10 | 8 | 9 | 10 | 11 |
Swell 1 Height (m) Direction Period (s) | — | SW 4 | SW 5 | SW 5 | — | — | NW 4 | — | SW 16 | SW 15 | SW 6 | SW 6 | SW 6 | SSW 6 | NNW 4 | W 3 | SW 13 | SW 15 | SW 15 | SW 15 |
| kJ | — | 5 | 6 | 4 | — | — | 3 | — | 10 | 9 | 66 | 25 | 13 | 3 | 6 | 1 | 7 | 8 | 8 | 8 |
Swell 2 Height (m) Direction Period (s) | — | — | — | NW 3 | — | — | — | — | — | — | SW 16 | SW 15 | SW 14 | SW 14 | W 3 | NNW 4 | — | — | — | S 12 |
| kJ | — | — | — | 2 | — | — | — | — | — | — | 10 | 8 | 8 | 8 | 1 | 1 | — | — | — | 3 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | W 15 | — | — | NE 4 | SW 6 | — | — | — | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | 4 | — | — | 1 | 1 | — | — | — | — |
Wind waves Height (m) Direction Period (s) | SSW 2 | — | WNW 3 | WSW 3 | SW 4 | WSW 4 | SW 6 | WSW 4 | WSW 5 | SW 5 | WNW 4 | NW 4 | NNW 4 | N 5 | — | NNE 4 | N 4 | N 4 | NNW 4 | N 4 |
| kJ | 1 | — | 5 | 4 | 23 | 24 | 16 | 26 | 69 | 100 | 20 | 19 | 37 | 47 | — | 1 | 10 | 9 | 7 | 6 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 285 | 219 | 249 | 285 | 569 | 51 | 557 | 251 | 246 | 251 | 792 | 179 | 514 | 192 | 187 | 284 | 208 | 273 | 284 | 241 |
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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