Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 20 Aug 2026:
- Best quality surf: Wednesday 26 Aug, 7PM (local time) - 4.5ft (1.4m), 5s period, SSW swell with cross-offshore winds.
- Most powerful swell: Wednesday 26 Aug, 10PM (local time) - 6ft (1.8m), 6s period, SSW swell with 262 kJ wave energy.
- Next surfable swell (1★+): Wednesday 26 Aug, 7PM (local time) - 4.5ft (1.4m), 5s 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 Wednesday (Aug 26) at 7PM. The primary swell is predicted to be 1.4m and 5s period. 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 6s and forecast to arrive on Wednesday (Aug 26) at 10PM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.3m 5s period and expected on Thursday (Aug 20) at 1PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 7PM (Wed 26th Aug) | 4.5ft (1.4m) 5s |
| Best Surf | 7PM (Wed 26th Aug) | 4.5ft (1.4m) 5s |
| Most Powerful | 10PM (Wed 26th Aug) | 6ft (1.8m) 6s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright, grab a brew and listen up. Rusty here. Let's be straight with you – this is a tough one for the Holy Island area. The forecast is a long, dry spell of nothing much, with a tiny flicker of hope way down the line.
The good news? There's basically none for the first week. We're looking at a solid run of tiny, weak swells and poor conditions from now until the tail end of August. The water is sitting at 64°F near Trearddur Bay, which is a touch warmer than normal for this time of year, but that's small comfort when there's nothing to ride.
The first signs of life don't pop up until Thursday, August 27th. That's your standout, and it's the only one worth getting excited about. On Thursday morning, a 10ft swell from the SW will roll in, with a short period of 7 seconds and moderate combined energy (731). The wind is light and cross-onshore in the morning, which is a bit lumpy, but it's due to swing to a light offshore from the north by Thursday afternoon. That afternoon session will see the swell still a solid 8ft, clean, and with a much better wind. The period is still short, so expect a bit of a bumpy, dumpy wave, but at this size, it'll have some punch. This one is for the experienced crew – 8ft is well into the range that's only for good surfers. The crowds at Trearddur Bay (Holy Island) can be a problem sometimes, but a mid-week, big-swell, average-period day might thin the pack out a bit.
After that Thursday blip, it's back to the doldrums. From Friday the 28th right through to the end of the forecast on September 3rd, we're looking at ankle-snappers and onshore junk. The swell drops back to under 3ft, with weak energy (under 54 on the scale) and mostly poor wind directions. There's a fair bit of fresh to strong wind in there, which will make the short-period, small swell a complete mess.
So, the bottom line: the only window is Thursday, August 27th. If you're a capable surfer and you can get a pass for the afternoon, you might score. For everyone else, it's a long wait for the next real swell.
Rusty.
Short Range ForecastModerate rain (total 16mm), heaviest on Wed night. Very mild (max 16°C on Wed night, min 13°C on Thu night). Winds decreasing (fresh winds from the N on Thu morning, light winds from the NE by Fri afternoon). | Days 4-6 Weather SummarySome drizzle, heaviest during Tue afternoon. Warm (max 22°C on Mon afternoon, min 14°C on Sat night). Mainly fresh winds. | ||||||||||||||||||||
Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | Wednesday 26 | |||||||||||||||
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 6 | SW 6 | SW 14 | 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 10 | SSW 4 | SSW 8 | SSW 6 |
Wave Graph  | |||||||||||||||||||||
 kJ | 16 | 10 | 8 | 7 | 7 | 7 | 8 | 8 | 8 | 8 | 7 | 7 | 8 | 7 | 7 | 7 | 7 | 9 | 42 | 94 | 193 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross-off | cross-off | off | cross-off | cross-off | cross | cross-off | cross-off | cross-off | off | cross-off | cross-off | cross-off | cross-off | cross | cross-off | cross-on | cross | 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 | 10:14AM1.98m | 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 | 4:11AM1.47m | 4:21PM1.52m | ||||||||
 |  |  |  |  | | | | | | | | | |  | |  | | | |  | |
 | 6:05 | — | — | 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 | 5 | — | — | — | 2 | — | — | — | — | — | — | — | — | — | — | — | 1 | — | — | 1 | 28 |
Temp °C | 15 | 15 | 14 | 14 | 15 | 14 | 13 | 15 | 15 | 15 | 16 | 17 | 21 | 22 | 19 | 21 | 20 | 17 | 20 | 21 | 19 |
Feels °C | 10 | 10 | 9 | 11 | 13 | 9 | 10 | 13 | 14 | 13 | 14 | 14 | 20 | 17 | 12 | 16 | 15 | 15 | 18 | 20 | 18 |
Swell 1 Height (m) Direction Period (s) | SW 6 | SW 6 | SSW 6 | SW 6 | W 4 | SW 13 | SW 15 | NNW 5 | NNW 4 | N 4 | SW 14 | SW 14 | SW 14 | SW 9 | SW 13 | SW 13 | SSE 4 | SSW 10 | NNE 5 | — | — |
| kJ | 16 | 10 | 4 | 1 | 1 | 7 | 8 | 19 | 4 | 3 | 7 | 7 | 8 | 3 | 7 | 7 | 2 | 9 | 2 | — | — |
Swell 2 Height (m) Direction Period (s) | SW 15 | SW 14 | SW 14 | SW 14 | SW 6 | — | — | SW 15 | SW 15 | SW 14 | — | — | SW 9 | SW 13 | SW 9 | SW 8 | SW 8 | SW 7 | S 13 | S 12 | — |
| kJ | 8 | 8 | 8 | 7 | 1 | — | — | 8 | 8 | 8 | — | — | 3 | 7 | 3 | 3 | 3 | 2 | 3 | 3 | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | SW 13 | — | — | — | SW 12 | — | — | SW 10 | — | — | NE 5 | N 6 | SW 13 | SW 7 | — | — | — |
| kJ | — | — | — | — | 7 | — | — | — | 6 | — | — | 4 | — | — | 1 | 1 | 7 | 2 | — | — | — |
Wind waves Height (m) Direction Period (s) | NNW 4 | N 5 | NNW 5 | NNW 5 | NNW 4 | NNW 5 | NNW 5 | NW 5 | — | — | N 4 | — | — | — | E 4 | E 5 | ENE 5 | NE 6 | SSW 4 | SSW 8 | SSW 6 |
| kJ | 31 | 76 | 102 | 39 | 10 | 40 | 25 | 6 | — | — | 1 | — | — | — | 9 | 14 | 17 | 24 | 42 | 94 | 193 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 284 | 514 | 192 | 192 | 284 | 184 | 178 | 273 | 163 | 184 | 292 | 163 | 246 | 163 | 276 | 380 | 332 | 297 | 275 | 275 | 155 |
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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