Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 21 Aug 2026:
- Best quality surf: Thursday 27 Aug, 4AM (local time) - 3.5ft (1.1m), 6s period, SSW swell with cross-offshore winds.
- Most powerful swell: Thursday 27 Aug, 4AM (local time) - 3.5ft (1.1m), 6s period, SSW swell with 91 kJ wave energy.
- Next surfable swell (1★+): Thursday 27 Aug, 4AM (local time) - 3.5ft (1.1m), 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 Thursday (Aug 27) at 4AM. The primary swell is predicted to be 1.1m and 6s period with a secondary swell of 0.1m and 12s. 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 1.1m 6s and forecast to arrive on Thursday (Aug 27) at 4AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 5s period and expected on Saturday (Aug 22) at 1AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 4AM (Thu 27th Aug) | 3.5ft (1.1m) 6s |
| Best Surf | 4AM (Thu 27th Aug) | 3.5ft (1.1m) 6s |
| Most Powerful | 4AM (Thu 27th Aug) | 3.5ft (1.1m) 6s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright, Rusty here, let’s look at what’s on offer for Trearddur Bay.
Honestly, mate, the next 16 days are a real struggle. We're looking at a long, painful stretch of flatness and onshore junk. The only break on the radar is Trearddur Bay (Holy Island), and it’s giving us next to nothing. There’s a gap of almost a week of truly poor surf before we even see a hint of a wave.
The week starts on Friday the 21st with tiny 0.3ft swell from the SW under a moderate north breeze. It’s basically a lake. Saturday and Sunday are the same story – flat, clean but flat. The water is sitting at 63°, which is a touch warmer than normal for this time of year, but it won’t help the lack of waves.
We finally see a pulse of energy arrive on Wednesday the 26th, with the swell bumping up to 1ft. The period is a short 8 seconds, so it’s weak, and the wind is light cross-shore. The combined energy is a measly 25. It’s poor. Thursday morning the 27th is the closest thing we get to a highlight. The swell is 3ft from the SSW with a 7-second period, and for a few hours we get a light offshore breeze from the NE. The combined energy climbs to 91, but it’s still weak. The file calls it “surfable but very ordinary,” and that’s being generous. It’s the best of a bad lot, but it’s not worth getting excited about.
The rest of the run is a write-off. Strong onshore winds hammer the place from Friday the 28th onwards, with a fresh breeze from the SW blowing 22 mph. The swell tries to build on the 30th of August to 4ft, and again on the 1st of September to 6ft, but the wind is straight onshore, ruining any chance of a clean wave. This setup looks far more interesting for kite surfing than paddle surfing, with a moderate cross-onshore and lumpy conditions. The combined energy on the 1st hits 180, but it’s all wind-chop.
Given how inconsistent this spot is, a blank run like this is more normal for the area. It’s a tough one. Forecasts can change, but right now, I’d leave the board in the car.
Rusty.
Short Range ForecastLight rain (total 3mm), mostly falling on Fri morning. Very mild (max 17°C on Sun night, min 13°C on Fri night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 9mm), mostly falling on Wed morning. Warm (max 21°C on Mon afternoon, min 14°C on Mon night). Wind will be generally light. | ||||||||||||||||||||
Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | Wednesday 26 | Thursday 27 | |||||||||||||||
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 14 | SW 13 | SW 13 | SW 15 | SW 15 | SW 15 | SW 14 | SW 14 | SW 14 | SW 14 | SW 13 | SW 13 | SW 13 | SW 13 | SSW 9 | SW 8 | SSW 5 | S 6 | SSW 7 | WNW 5 | SSW 7 |
Wave Graph  | |||||||||||||||||||||
 kJ | 7 | 7 | 7 | 8 | 8 | 8 | 8 | 7 | 7 | 8 | 7 | 7 | 7 | 7 | 8 | 18 | 30 | 50 | 54 | 28 | 21 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross | cross | cross-off | off | cross-off | cross-off |
High Tide | 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 | 10:26AM4.89m | 10:33PM5.32m | 10:57AM5.08m | 11:04PM5.51m | ||||||||
Low Tide | 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 | 4:11AM1.47m | 4:21PM1.52m | 4:43AM1.19m | 4:52PM1.28m | ||||||||
 |  |  | | | | | | |  | |  |  | | |  | |  | |  | | |
 | 6:07 | — | — | 6:09 | — | — | 6:11 | — | — | 6:13 | — | — | 6:13 | — | — | 6:16 | — | — | 6:18 | — | — |
 | — | 8:34 | — | — | 8:31 | — | — | 8:29 | — | — | 8:27 | — | — | 8:24 | — | — | 8:22 | — | — | 8:20 | — |
mm | 3 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 7 | 1 | 1 | — | 2 | 2 |
Temp °C | 15 | 16 | 14 | 13 | 14 | 14 | 15 | 16 | 17 | 19 | 21 | 19 | 18 | 20 | 18 | 16 | 19 | 19 | 19 | 19 | 18 |
Feels °C | 11 | 12 | 10 | 10 | 10 | 12 | 12 | 13 | 14 | 18 | 17 | 14 | 16 | 15 | 14 | 15 | 18 | 18 | 20 | 19 | 19 |
Swell 1 Height (m) Direction Period (s) | SW 6 | SW 6 | SW 13 | SW 15 | SW 15 | SW 15 | SW 14 | SW 14 | SW 14 | SW 10 | SW 9 | SW 9 | — | SW 8 | SSW 9 | SW 8 | SW 8 | SW 7 | SSW 7 | SSW 7 | SSW 7 |
| kJ | 1 | 1 | 7 | 8 | 8 | 8 | 8 | 7 | 7 | 4 | 3 | 3 | — | 3 | 8 | 18 | 17 | 13 | 54 | 28 | 21 |
Swell 2 Height (m) Direction Period (s) | SW 14 | SW 13 | S 5 | — | — | S 12 | — | — | SW 11 | SW 14 | NE 4 | SW 13 | SW 13 | — | S 13 | NNE 4 | NE 4 | S 12 | S 12 | — | — |
| kJ | 7 | 7 | 1 | — | — | 3 | — | — | 5 | 8 | 1 | 7 | 7 | — | 3 | 2 | 1 | 3 | 3 | — | — |
Swell 3 Height (m) Direction Period (s) | SW 13 | — | — | — | — | W 12 | — | — | — | — | SW 13 | — | SW 9 | SW 13 | — | S 13 | — | — | — | S 12 | — |
| kJ | 7 | — | — | — | — | 3 | — | — | — | — | 7 | — | 3 | 7 | — | 3 | — | — | — | 3 | — |
Wind waves Height (m) Direction Period (s) | NNW 5 | NNW 4 | NNW 5 | NNW 5 | NNW 5 | N 5 | N 4 | N 4 | NE 2 | — | — | E 3 | NE 5 | ENE 3 | NE 5 | S 4 | SSW 5 | S 6 | WNW 4 | WNW 5 | W 4 |
| kJ | 48 | 20 | 28 | 32 | 23 | 16 | 5 | 2 | 1 | — | — | 6 | 7 | 6 | 17 | 4 | 30 | 50 | 34 | 25 | 14 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 192 | 284 | 187 | 178 | 284 | 208 | 208 | 301 | 163 | 246 | 249 | 249 | 276 | 249 | 267 | 288 | 195 | 8 | 0 | 8 | 235 |
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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