Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 5 Sep 2026:
- Most powerful swell: Sunday 6 Sep, 7PM (local time) - 5.5ft (1.7m), 6s period, SSW swell with 223 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 1.7m 6s and forecast to arrive on Sunday (Sep 06) at 7PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.7m 4s period and expected on Saturday (Sep 12) at 7AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 7PM (Sun 6th Sep) | 5.5ft (1.7m) 6s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Right then, let’s have a look at what’s going down at Trearddur Bay. I'll be straight with you—it’s a bleak one. The water’s sitting at 63°, which is a touch warmer than normal for this time of year, so at least you won’t be freezing while you stare at the flatness.
Honestly, for the whole run, there’s barely a pulse. From Saturday the 5th through to the 20th, it’s all poor surf. The biggest issue is the wind. It’s mostly cross-onshore or onshore, and pretty fresh to strong a lot of the time, which just chops up anything that tries to arrive. Saturday kicks off with a weak 3ft at 5 seconds and it only goes downhill from there.
The weekend of the 5th and 6th sees some push—up to 5ft on Sunday afternoon—but it’s all cross-onshore and messy. Monday the 7th has a funky 14-second period early, but the swell is a pathetic 1ft, so there’s nothing to ride anyway.
There’s a moment on Tuesday the 8th where the swell bumps to 6ft with a 6-second period, the biggest of the whole window. But it’s fresh cross-onshore, lumpy, and a bit of a mess. That’s your best size-wise, but it’s not going to be any good. There’s some energy behind it, but it’s just not clean.
We go through a long stretch where it dies completely. From the 12th through to the 20th, it’s mostly under 2ft, with a lot of readings at 0.3ft or even nothing at all. Wednesday the 9th has a brief lull in wind, but the waves are tiny. Thursday the 10th and Friday the 11th pick up a bit again—up to 5ft with a cross-shore breeze on the 11th—but it’s still poor quality and lumpy. After that, it’s a dead loss. From the 12th to the 20th, it’s a flat spell. You might as well find something else to do.
The only clean windows are the 12th and the 19th, when the wind goes offshore, but there’s simply no swell at all—just 0.7ft or nothing. It's a classic flat spell for a spot like this; it's a fickle break, so it's not a surprise. There’s nothing that’s going to be any good for anyone. With the swell that does show up being mostly under 5ft and blown out, you’re not getting any decent waves. This is more of a kite-surfing week than a surfing one, to be honest.
Keep an eye on it, but don’t hold your breath. Forecasts can change, but right now, I’d dust off the longboard and maybe take up fishing.
Rusty
Short Range ForecastLight rain (total 6mm), mostly falling on Mon afternoon. Very mild (max 18°C on Sun afternoon, min 13°C on Mon night). Winds increasing (light winds from the WSW on Sat morning, strong winds from the S by Sun morning). | Days 4-6 Weather SummaryModerate rain (total 14mm), heaviest on Thu night. Very mild (max 15°C on Tue afternoon, min 13°C on Tue morning). Winds decreasing (fresh winds from the W on Tue morning, light winds from the SW by Wed night). | ||||||||||||||||||||
Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | |||||||||||||||
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 5 | SW 6 | SSW 4 | SSW 6 | SSW 6 | SW 6 | SW 14 | SW 6 | WSW 5 | WSW 6 | W 5 | NW 5 | WNW 5 | NW 4 | SW 4 | SW 4 | SSW 5 | SW 6 | NW 6 | NW 5 | NW 5 |
Wave Graph  | |||||||||||||||||||||
 kJ | 30 | 16 | 28 | 115 | 156 | 152 | 33 | 165 | 128 | 194 | 108 | 115 | 87 | 24 | 6 | 24 | 110 | 159 | 133 | 96 | 42 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | cross-on | cross-on | cross-on | cross-on | on | on | cross-on | cross-on | cross-on | cross | cross | on | cross-on | cross-on | cross-on | cross-on | cross | cross | cross-off |
High Tide | 5:21PM4.55m | 6:18AM4.51m | 7:01PM4.59m | 7:54AM4.65m | 8:23PM4.91m | 9:02AM4.96m | 9:21PM5.29m | 9:53AM5.26m | 10:08PM5.63m | 10:36AM5.47m | 10:49PM5.85m | 11:14AM5.59m | 11:28PM5.95m | ||||||||
Low Tide | 10:59AM2.01m | 11:50PM1.99m | 12:31PM2.14m | 1:25AM1.84m | 1:57PM1.96m | 2:38AM1.44m | 3:00PM1.61m | 3:33AM1.02m | 3:50PM1.24m | 4:19AM0.68m | 4:32PM0.95m | 5:00AM0.47m | 5:11PM0.75m | ||||||||
 |  |  |  |  |  | | |  | | | | | |  | | |  | | | | |
 | 6:33 | — | — | 6:35 | — | — | 6:37 | — | — | 6:39 | — | — | 6:39 | — | — | 6:41 | — | — | 6:43 | — | — |
 | — | 7:59 | — | — | 7:57 | — | — | 7:53 | — | — | 7:52 | — | — | 7:50 | — | — | 7:46 | — | — | 7:45 | — |
mm | — | — | 1 | 1 | — | — | — | 2 | 2 | — | — | 1 | — | — | — | — | — | 13 | 1 | — | — |
Temp °C | 14 | 14 | 15 | 17 | 18 | 17 | 15 | 16 | 15 | 14 | 15 | 14 | 13 | 14 | 15 | 15 | 15 | 15 | 15 | 15 | 14 |
Feels °C | 10 | 10 | 9 | 10 | 11 | 12 | 11 | 10 | 9 | 7 | 9 | 7 | 10 | 11 | 12 | 11 | 10 | 11 | 9 | 10 | 9 |
Swell 1 Height (m) Direction Period (s) | NNW 5 | WNW 4 | SW 13 | SW 13 | — | SW 12 | SW 14 | — | — | SW 11 | SW 11 | SW 6 | SW 5 | SW 5 | — | — | — | — | SW 8 | SW 8 | SW 7 |
| kJ | 17 | 3 | 7 | 7 | — | 6 | 33 | — | — | 5 | 5 | 16 | 5 | 4 | — | — | — | — | 57 | 28 | 14 |
Swell 2 Height (m) Direction Period (s) | SW 7 | NNW 5 | — | — | — | W 17 | — | — | — | — | W 10 | S 11 | — | — | SW 8 | — | — | — | SSW 7 | — | SW 5 |
| kJ | 7 | 2 | — | — | — | 6 | — | — | — | — | 2 | 2 | — | — | 2 | — | — | — | 21 | — | 4 |
Swell 3 Height (m) Direction Period (s) | SW 14 | NW 4 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | 7 | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | WSW 5 | SW 6 | SSW 4 | SSW 6 | SSW 6 | SW 6 | WSW 4 | SW 6 | WSW 5 | WSW 6 | W 5 | NW 5 | WNW 5 | NW 4 | SW 4 | SW 4 | SSW 5 | SW 6 | NW 6 | NW 5 | NW 5 |
| kJ | 30 | 16 | 28 | 115 | 156 | 152 | 28 | 165 | 128 | 194 | 108 | 115 | 87 | 24 | 6 | 24 | 110 | 159 | 133 | 96 | 42 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 51 | 235 | 186 | 312 | 347 | 167 | 51 | 326 | 280 | 280 | 179 | 192 | 178 | 251 | 179 | 179 | 275 | 96 | 72 | 548 | 192 |
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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