Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 19 Aug 2026:
- Best quality surf: Wednesday 26 Aug, 1AM (local time) - 5ft (1.6m), 8s period, SW swell with cross-offshore winds.
- Most powerful swell: Wednesday 26 Aug, 4AM (local time) - 6ft (1.8m), 8s period, SSW swell with 398 kJ wave energy.
- Next surfable swell (1★+): Tuesday 25 Aug, 10PM (local time) - 4.5ft (1.4m), 6s period with SSW swell.
Best Forecast Surf Conditions for Trearddur Bay (Holy Island) this week:
The surf forecast for Trearddur Bay (Holy Island) over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Tuesday (Aug 25) at 10PM. The primary swell is predicted to be 1.4m and 6s period with a secondary swell of 0.1m and 13s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Trearddur Bay (Holy Island) in the next 16 days are 1.8m 8s and forecast to arrive on Wednesday (Aug 26) at 4AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.2m 5s period and expected on Thursday (Aug 20) at 1PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 10PM (Tue 25th Aug) | 4.5ft (1.4m) 6s |
| Best Surf | 1AM (Wed 26th Aug) | 5ft (1.6m) 8s |
| Most Powerful | 4AM (Wed 26th Aug) | 6ft (1.8m) 8s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright, Rusty here. Let's talk about what's on the table for Trearddur Bay.
Honestly, it's a bit of a tough stretch ahead. For the next week, we're looking at a long, flat spell with barely a ripple. From Wednesday the 19th right through to Tuesday the 25th, the swell is tiny, with heights mostly between 0.3ft and 3ft and periods under 8 seconds. The combined energy is weak, often in the single digits (44 or less), and the conditions are just not cooperating. The wind is mostly cross-off or clean, but with no swell to work with, it's just a pretty lake. The water temperature is about average for this time of year, but honestly, you won't need a wetsuit for a paddle – just a board won't do much.
Then, on Wednesday the 26th of August, we get a bit of a pulse. The morning sees a 6ft swell from the south, with a period of 8 seconds and a big jump in energy to 539 (moderate). The wind is from the east at 9 mph, keeping it clean. This is our best bet in the whole 16-day window, but it's still a marginal call. The swell direction is from the south, which is close to the optimum SW, so it should wrap in okay. It's big enough for a decent wave, but over 5ft, it might be a bit much for beginners, and the short period means it'll be a bit crumbly and close together. The afternoon turns to trash with cross-onshore winds from the south, so get it in the morning if you can.
After that, the rest of the forecast is a write-off. The 27th through the 3rd of September is a mix of tiny swells, strong cross and onshore winds, and generally blown-out, messy conditions. The 30th of August has a 7ft swell, but it's accompanied by a 22 mph cross-shore wind that will turn it into a washing machine (combined energy 403). That's more of a kite-surfing scene than a paddle session.
So, to sum it up: the only real window is Wednesday morning, the 26th of August. It's a short, promising window, but it's a one-off. The rest of the time, you're better off with a cold one and a spot on the beach.
Rusty.
Short Range ForecastModerate rain (total 17mm), heaviest on Wed night. Very mild (max 16°C on Wed afternoon, min 13°C on Thu night). Mainly fresh winds. | Days 4-6 Weather SummaryMostly dry. Very mild (max 18°C on Mon morning, min 12°C on Fri night). Wind will be generally light. | ||||||||||||||||||||
Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | |||||||||||||||
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) | WSW 4 | SSW 4 | SW 5 | SW 6 | SW 7 | SW 14 | SW 14 | SW 13 | SW 13 | SW 15 | SW 15 | SW 15 | SW 14 | SW 14 | SW 14 | SW 14 | SW 14 | SW 13 | SSW 4 | SSW 4 | SW 8 |
Wave Graph  | |||||||||||||||||||||
 kJ | 24 | 18 | 42 | 21 | 11 | 8 | 7 | 7 | 7 | 8 | 8 | 8 | 8 | 7 | 8 | 8 | 7 | 7 | 10 | 18 | 344 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | off | cross-off | off | off | glassy | on | cross-off |
High Tide | 3:32PM4.68m | 3:52AM4.62m | 4:23PM4.44m | 4:52AM4.29m | 5:32PM4.26m | 6:23AM4.10m | 7:07PM4.27m | 8:04AM4.17m | 8:27PM4.49m | 9:08AM4.41m | 9:19PM4.79m | 9:52AM4.67m | 9:59PM5.08m | ||||||||
Low Tide | 9:26AM1.59m | 9:39PM1.83m | 10:14AM1.98m | 10:37PM2.18m | 11:17AM2.31m | 11:58PM2.41m | 12:45PM2.45m | 1:37AM2.37m | 2:08PM2.34m | 2:47AM2.11m | 3:05PM2.09m | 3:35AM1.78m | 3:46PM1.80m | ||||||||
 | |  | |  |  |  | | | |  |  | | | | | | | | | | |
 | 6:03 | — | — | 6:05 | — | — | 6:07 | — | — | 6:09 | — | — | 6:11 | — | — | 6:13 | — | — | 6:13 | — | — |
 | — | 8:37 | — | — | 8:36 | — | — | 8:34 | — | — | 8:31 | — | — | 8:29 | — | — | 8:27 | — | — | 8:24 | — |
mm | 1 | 1 | 7 | 2 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 15 | 16 | 16 | 15 | 15 | 14 | 14 | 15 | 14 | 13 | 14 | 14 | 14 | 16 | 15 | 18 | 18 | 17 | 17 | 17 | 16 |
Feels °C | 11 | 11 | 14 | 10 | 9 | 10 | 10 | 11 | 10 | 10 | 10 | 11 | 11 | 14 | 13 | 17 | 15 | 15 | 16 | 16 | 14 |
Swell 1 Height (m) Direction Period (s) | SW 16 | NW 4 | SW 5 | SW 6 | SW 7 | SSW 6 | SW 6 | NNW 4 | SW 13 | SW 15 | SW 15 | SW 15 | N 4 | NNW 4 | SW 14 | SW 14 | SW 14 | SW 13 | SW 13 | SW 13 | SW 8 |
| kJ | 10 | 2 | 42 | 21 | 11 | 4 | 1 | 12 | 7 | 8 | 8 | 8 | 10 | 3 | 8 | 8 | 7 | 7 | 7 | 7 | 338 |
Swell 2 Height (m) Direction Period (s) | SW 16 | S 15 | SW 16 | SW 15 | SW 14 | SW 14 | SW 14 | SW 5 | S 5 | — | — | S 12 | SW 14 | SW 14 | — | — | — | — | — | — | SW 13 |
| kJ | 10 | 5 | 10 | 8 | 8 | 8 | 7 | 1 | 1 | — | — | 3 | 8 | 7 | — | — | — | — | — | — | 6 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | SW 13 | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | — | — | — | — | — | — | 7 | — | — | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | WSW 4 | SSW 4 | WNW 4 | NNW 4 | N 5 | N 5 | NNW 5 | WNW 4 | NNW 5 | NNW 5 | NNW 4 | N 4 | — | NW 2 | — | — | — | SW 3 | SSW 4 | SSW 4 | SSW 7 |
| kJ | 24 | 18 | 11 | 43 | 51 | 53 | 25 | 3 | 42 | 22 | 9 | 8 | — | 1 | — | — | — | 4 | 10 | 18 | 344 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 246 | 246 | 174 | 179 | 192 | 179 | 179 | 179 | 273 | 187 | 187 | 208 | 267 | 292 | 246 | 246 | 246 | 246 | 184 | 155 | 0 |
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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