
Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 11 Aug 2026:
- Most powerful swell: Friday 14 Aug, 1AM (local time) - 2.5ft (0.8m), 5s period, SW swell with 34 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 0.8m 5s and forecast to arrive on Friday (Aug 14) at 1AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.6m 4s period and expected on Saturday (Aug 15) at 1PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 1AM (Fri 14th Aug) | 2.5ft (0.8m) 5s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a look at what’s cookin’ for Trearddur Bay over the next couple of weeks. Gotta be straight with you – the surf diary is pretty bleak for a long stretch. We’ve got almost two full weeks where you’d struggle to get wet. Let’s break it down.
We kick off from today, the 11th of August, right through to the morning of Sunday the 23rd of August. That’s nearly two weeks of flat or tiny, choppy junk. The water temperature is sitting at 63°, which is a touch warmer than normal for this time of year, so you won’t be freezing your buns off while you’re waiting for a wave that never comes. But that's the only good news. We’re looking at a lot of onshore muck, weak energy readings in the single digits or low double digits, and swell heights barely scraping 2 feet. There are a few moments of clean offshore wind on the 17th of August – Monday – with a fresh NE breeze, but the swell is a pathetic 1 feet. You’d need a stand-up paddleboard, not a surfboard. Basically, forget it until the end of the month.
There’s a big gap of silence and then finally, on the morning of Sunday the 23rd of August, a proper SSW swell swings in at 5 feet with a 7-second period. The energy finally pumps up to 265 – moderate. Problem is, the wind is onshore from the SW, so it’s gonna be messy. Trearddur Bay (Holy Island) is fairly exposed to this direction, and it’s a beginner spot, but that 5 feet mark is right on the edge for beginners. It might be rideable, but it won’t be pretty. The afternoon bumps up to 6 feet (energy 392), but the wind cranks onshore from the S at 22 miles per hour – lumpy as hell.
Now, if you’re an expert and don’t mind a challenge, keep an eye on Monday the 24th of August. We’ve got a 8 feet swell from the SW (energy 890), but it’s hammered by a near-gale cross-onshore wind at 31 miles per hour. That’s blown-out, heavy, and honestly, with that kind of wind and size at a beach setup, it’s looking more like a kite-surfing day than a paddling day. The period is only 9 seconds, so it’s not proper groundswell anyway. Rough.
The very end of the outlook, Wednesday the 26th of August afternoon, finally offers a tiny glimmer. A 2 feet WNW swell with clean conditions and a cross-offshore wind from the NNW. It’s still small, but the energy is weak (24), and you’d be scratching for anything waist-high. At least it’s clean.
So, the only true standout – and I use the term loosely – is the Sunday the 23rd of August morning if you’re a local who just needs to get wet. It’s the biggest push of the whole forecast. But for good, clean waves? There isn’t a single day in this 16-day window that’s worth a drive. Keep the board waxed in the garage and wait for the next weather system.
Rusty.
Short Range ForecastMostly dry. Warm (max 24°C on Wed afternoon, min 17°C on Thu night). Wind will be generally light. | Days 4-6 Weather SummarySome drizzle, heaviest during Sun afternoon. Very mild (max 18°C on Fri afternoon, min 14°C on Sun afternoon). Wind will be generally light. | ||||||||||||||||||||
Tuesday 11 | Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | |||||||||||||||
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) | SSW 6 | SSW 3 | S 11 | SW 12 | SW 12 | SW 10 | SW 10 | SW 11 | SW 5 | NW 4 | WNW 4 | SSW 6 | NW 4 | WNW 4 | W 3 | SW 4 | SW 4 | SSW 3 | SSW 4 | SW 4 | SSW 5 |
Wave Graph | |||||||||||||||||||||
4 | 2 | 2 | 6 | 6 | 4 | 4 | 4 | 34 | 28 | 6 | 4 | 16 | 2 | 1 | 1 | 1 | 1 | 6 | 5 | 3 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | cross | cross-on | on | cross-on | on | on | cross-on | cross-off | cross | cross | cross | cross | cross-on | cross-on | cross-on | glassy | off | off | off |
High Tide | 10:01AM5.19m | 10:21PM5.51m | 10:50AM5.42m | 11:07PM5.78m | 11:35AM5.56m | 11:49PM5.94m | 12:16PM5.58m | 00:30AM5.96m | 12:56PM5.52m | 1:10AM5.85m | 1:35PM5.37m | 1:49AM5.63m | 2:12PM5.16m | 2:28AM5.33m | |||||||
Low Tide | 4:01PM1.21m | 4:33AM0.72m | 4:48PM0.94m | 5:19AM0.45m | 5:32PM0.74m | 6:02AM0.32m | 6:14PM0.67m | 6:44AM0.35m | 6:54PM0.71m | 7:25AM0.53m | 7:34PM0.87m | 8:05AM0.82m | 8:13PM1.14m | ||||||||
5:50 | — | — | 5:52 | — | — | 5:54 | — | — | 5:54 | — | — | 5:56 | — | — | 5:58 | — | — | 6:01 | — | — | |
— | 8:54 | — | — | 8:52 | — | — | 8:51 | — | — | 8:49 | — | — | 8:46 | — | — | 8:45 | — | — | 8:43 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | — | — | — |
Temp °C | 19 | 20 | 20 | 22 | 24 | 24 | 21 | 22 | 21 | 15 | 18 | 18 | 15 | 17 | 16 | 16 | 14 | 14 | 16 | 17 | 15 |
Feels °C | 15 | 18 | 19 | 18 | 21 | 23 | 20 | 22 | 21 | 11 | 15 | 13 | 12 | 15 | 15 | 14 | 12 | 13 | 11 | 12 | 12 |
Swell 1 Height (m) Direction Period (s) | SSW 6 | SW 6 | SSW 3 | SW 12 | SSW 3 | SW 5 | SW 8 | SW 11 | SW 5 | SW 5 | N 4 | SSW 6 | SW 5 | NNW 4 | W 3 | SW 4 | SW 4 | — | SSW 4 | SW 4 | SSW 5 |
4 | 1 | 1 | 5 | 1 | 1 | 3 | 4 | 34 | 6 | 3 | 4 | 1 | 6 | 1 | 1 | 1 | — | 6 | 5 | 3 | |
Swell 2 Height (m) Direction Period (s) | — | — | SW 6 | SW 12 | SW 12 | SW 10 | SW 5 | S 11 | S 11 | — | SW 5 | — | — | SW 6 | S 5 | — | — | — | — | — | N 3 |
— | — | 1 | 6 | 6 | 4 | 1 | 2 | 2 | — | 3 | — | — | 1 | 1 | — | — | — | — | — | 1 | |
Swell 3 Height (m) Direction Period (s) | — | — | S 11 | W 10 | SW 6 | — | SW 10 | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
— | — | 2 | 2 | 1 | — | 4 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | — | SSW 3 | — | SSW 3 | — | — | SSW 2 | SW 2 | — | NW 4 | WNW 4 | NW 3 | NW 4 | WNW 4 | — | — | — | SSW 3 | — | NNE 3 | — |
— | 2 | — | 3 | — | — | 1 | 1 | — | 28 | 6 | 5 | 16 | 2 | — | — | — | 1 | — | 4 | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 284 | 306 | 163 | 161 | 182 | 178 | 179 | 249 | 192 | 192 | 161 | 192 | 179 | 358 | 195 | 246 | 249 | 285 | 163 | 179 | 163 |
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.











