Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 20 Aug 2026:
- Most powerful swell: Wednesday 26 Aug, 10PM (local time) - 3.5ft (1.1m), 6s period, SSW swell with 82 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 1.1m 6s and forecast to arrive on Wednesday (Aug 26) at 10PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.2m 6s period and expected on Friday (Aug 21) at 4AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 10PM (Wed 26th 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 get into it. I’ve looked over the whole 16-day window for Trearddur Bay (Holy Island), and I’d be lying if I said it looked good. There’s a long stretch of flatness and wind issues. We don’t get a real recommendation until the last few days, and even then, it’s a bit of a close call. Let's break it down.
For nearly the entire first week and a half, Trearddur Bay is offering next to nothing. The swell barely lifts above ankle-thigh high, with most days showing just 0.3ft to 1.3ft, and short periods. The wind is mostly cross-off or cross, but with such minimal energy, there’s nothing to ride. The first decent pulse doesn’t show up until the 26th of August, bringing 3.9ft from the south with a short period, but the wind is cross-onshore and the conditions are poor. It’s a no-go.
The 28th of August afternoon sees a bump in size to 4.9ft from the southwest, with combined energy hitting 119 (moderate energy), but again, onshore wind spoils it. The following day, the 29th, is the first time we see some real size: 6.6ft to 5.9ft from the west-southwest, with combined energy reaching 350 (strong) on the morning. The swell is short period though, and with a cross-onshore wind, it’s more of a choppy mess. For a beach-and-reef setup like Trearddur Bay, that strong cross-onshore wind and lumpy texture means this might actually look better for kite surfing than paddling.
The standout moment, and the only real window worth mentioning, lands on the 3rd of September. Thursday afternoon sees 5.9ft from the southwest with a short period, and combined energy at 295 (strong). The wind eases to a gentle breeze and is cross-onshore, making for slightly cleaner, though still a little bumpy, conditions. It’s not perfect, but it’s the best we’ve got. The offshore direction for Trearddur Bay (Holy Island) is from the NE, so this swell isn't quite aligned ideally, but with the size and moderate energy, you might find a few lumpy, workable waves for a session if you’re keen. The break is inconsistent, so don’t expect much, but it’s the one to watch.
Water temperature on the first date is 63.7°, which is a touch warmer than average for the time of year.
So overall, it's a long, flat wait. The 3rd of September is your only real chance, and it’s a gamble.
Short Range ForecastLight rain (total 3mm), mostly falling on Thu night. Very mild (max 16°C on Fri afternoon, min 13°C on Thu night). Winds decreasing (fresh winds from the N on Thu afternoon, light winds from the N by Sun morning). | Days 5-7 Weather SummaryLight rain (total 9mm), mostly falling on Tue night. Warm (max 21°C on Mon afternoon, min 15°C on Sun afternoon). Winds increasing (calm on Mon morning, fresh winds from the ENE by Tue afternoon). | |||||||||||||||||||
Thu 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | Wednesday 26 | ||||||||||||||
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 6 | SW 14 | SW 14 | SW 13 | SW 13 | SW 15 | SW 15 | SW 15 | SW 14 | SW 14 | SW 13 | SW 14 | SW 13 | SW 13 | SW 13 | SW 13 | SE 3 | S 5 | SSW 5 | SSW 6 |
Wave Graph  | ||||||||||||||||||||
 kJ | 10 | 8 | 7 | 7 | 7 | 8 | 8 | 8 | 8 | 7 | 7 | 8 | 7 | 7 | 7 | 7 | 7 | 70 | 48 | 56 |
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 | cross-off | cross-off | off | cross-off | cross | cross-off | cross-off | cross-off | cross-off | cross-on | cross-on | cross |
High Tide | 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 | 10:26AM4.89m | 10:33PM5.32m | |||||||
Low Tide | 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 | 4:11AM1.47m | 4:21PM1.52m | ||||||||
 |  |  | |  |  | | | | | | |  |  | | |  | | |  | |
 | — | — | 6:07 | — | — | 6:09 | — | — | 6:11 | — | — | 6:13 | — | — | 6:13 | — | — | 6:16 | — | — |
 | 8:36 | — | — | 8:34 | — | — | 8:31 | — | — | 8:29 | — | — | 8:27 | — | — | 8:24 | — | — | 8:22 | — |
mm | — | 1 | 2 | — | — | — | — | — | — | — | — | — | — | — | — | — | 8 | 1 | — | — |
Temp °C | 15 | 14 | 15 | 16 | 14 | 14 | 14 | 15 | 14 | 16 | 17 | 20 | 21 | 19 | 18 | 21 | 20 | 17 | 18 | 16 |
Feels °C | 9 | 9 | 11 | 12 | 10 | 10 | 10 | 13 | 13 | 13 | 15 | 18 | 19 | 12 | 14 | 15 | 17 | 14 | 14 | 14 |
Swell 1 Height (m) Direction Period (s) | SW 6 | SSW 6 | NNW 5 | W 4 | SW 13 | SW 15 | SW 15 | SW 15 | N 4 | N 4 | SW 13 | SW 10 | SW 9 | SW 9 | NE 6 | SSE 4 | NE 6 | NE 5 | SSW 8 | SSW 6 |
| kJ | 10 | 3 | 39 | 1 | 7 | 8 | 8 | 8 | 3 | 1 | 7 | 4 | 3 | 3 | 8 | 3 | 20 | 1 | 6 | 56 |
Swell 2 Height (m) Direction Period (s) | SW 14 | SW 14 | SW 6 | SW 6 | S 5 | — | — | S 12 | SW 14 | SW 14 | — | SW 14 | SW 13 | SW 13 | SSE 4 | SW 13 | SSW 8 | S 12 | — | SSW 7 |
| kJ | 8 | 8 | 1 | 1 | 1 | — | — | 3 | 8 | 7 | — | 8 | 7 | 7 | 2 | 7 | 7 | 3 | — | 21 |
Swell 3 Height (m) Direction Period (s) | — | — | SW 14 | SW 13 | — | — | — | W 12 | — | — | — | — | — | — | SW 13 | SW 8 | SW 13 | — | S 12 | S 12 |
| kJ | — | — | 7 | 7 | — | — | — | 3 | — | — | — | — | — | — | 7 | 3 | 7 | — | 3 | 3 |
Wind waves Height (m) Direction Period (s) | N 5 | NNW 5 | — | NNW 4 | NNW 5 | NNW 5 | NNW 5 | N 5 | — | NNW 4 | ENE 2 | — | — | E 4 | E 3 | ENE 3 | SE 3 | S 5 | SSW 5 | — |
| kJ | 73 | 66 | — | 10 | 31 | 24 | 25 | 11 | — | 1 | 1 | — | — | 12 | 1 | 9 | 7 | 70 | 48 | — |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 514 | 192 | 192 | 284 | 219 | 179 | 284 | 187 | 184 | 292 | 163 | 246 | 249 | 249 | 286 | 322 | 307 | 286 | 186 | 51 |
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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