Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 15 Aug 2026:
- Most powerful swell: Thursday 20 Aug, 4AM (local time) - 4.5ft (1.3m), 5s period, WSW swell with 75 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 1.3m 5s and forecast to arrive on Thursday (Aug 20) at 4AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.3m 6s period and expected on Friday (Aug 21) at 1AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 4AM (Thu 20th Aug) | 4.5ft (1.3m) 5s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Right, let’s have a look at what we’ve got, surfers. It’s Rusty here, and I’ve got to be straight with you – the next couple of weeks are looking pretty grim for the majority of us. We’ve got a bit of a flat spell on the horizon.
Our only real option on the board is Trearddur Bay (Holy Island). Problem is, it’s a spot marked as *inconsistent*, so we’re not even sure it’s going to break properly. The main issue is that the swell is tiny, and the wind is often not in our favour. This is one of those times where you’d be better off finding something else to do than stare out to sea.
Let’s take it day by day. For the first few days, we’re looking at nothing but knee-high dribble at best, around 0.3 ft. The water temp is sitting at 63°F, which is a touch warmer than normal for this time of year – that’s about the only good news. The wind is a bit of a mess, with cross-off breezes, so it’ll be clean but empty. There’s just no energy in the water at all, with the combined swell energy at a pitiful 2.
We get a bit of a bump mid-week – the 17th and 18th see the swell nudge up to 1 ft and 2 ft, but it’s short-period windswell and the wind is all over the place. It’s going to be lumpy and choppy, with the energy rising only to a weak 21. Honestly, it’s not worth getting wet for.
The 19th sees a little more push, with waves hitting 3 ft, but the wind is fresh and onshore, making it a mess. That’s more of a kite-surfing wind than a paddle-surfing one, if you ask me. The energy picks up to 38, but with the quality so poor, it’s still a pass. Then the 20th is more of the same – 3 ft but with a moderate cross-onshore chop.
After that, the swell falls away pretty quickly. From the 21st onward, we’re back down to ankle-slashers, around 0.3 ft. There are some clean days with offshore winds and glassy conditions, especially around the 22nd and 23rd, with winds up to 19 mph but blowing offshore. The period does stretch out to 14-15 seconds, which would normally get us excited, but it’s just not enough swell. There’s no energy behind it. It’ll be pretty as a picture but totally flat. The energy levels stay in the single digits for the rest of the window.
So, there you have it. We’re looking at a solid two weeks of nada. It’s a blank run that’s pretty normal for this stretch of coast, and forecasts can change, but right now, I’d be doing anything but planning a surf trip. Keep the board in the car, maybe, but don’t get your hopes up.
Rusty.
Short Range ForecastLight rain (total 5mm), mostly falling on Mon night. Very mild (max 18°C on Mon night, min 14°C on Sat morning). Winds increasing (calm on Sat night, fresh winds from the S by Mon night). | Days 4-6 Weather SummaryLight rain (total 8mm), mostly falling on Tue night. Very mild (max 17°C on Tue morning, min 14°C on Tue night). Winds decreasing (fresh winds from the W on Wed morning, light winds from the NW by Thu afternoon). | ||||||||||||||||||||
Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | |||||||||||||||
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) | W 8 | SW 6 | SW 6 | — | SW 5 | SW 4 | WNW 4 | SW 5 | SSW 4 | SW 4 | SW 6 | W 4 | W 4 | SW 4 | SW 5 | WNW 5 | SW 6 | SW 6 | SW 14 | WNW 4 | SW 13 |
Wave Graph | |||||||||||||||||||||
1 | 1 | 1 | 0 | 1 | 6 | 5 | 4 | 28 | 16 | 15 | 12 | 28 | 18 | 56 | 27 | 11 | 8 | 7 | 7 | 7 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | off | glassy | on | cross-on | cross | on | on | cross-on | cross-on | cross-on | cross-on | on | cross-on | cross-on | cross-on | cross-off | cross-off | cross-off | off |
High Tide | 12:56PM5.52m | 1:10AM5.85m | 1:35PM5.37m | 1:49AM5.63m | 2:12PM5.16m | 2:28AM5.33m | 2:51PM4.93m | 3:07AM4.98m | 3:32PM4.68m | 3:52AM4.62m | 4:23PM4.44m | 4:52AM4.29m | 5:32PM4.26m | ||||||||
Low Tide | 6:54PM0.71m | 7:25AM0.53m | 7:34PM0.87m | 8:05AM0.82m | 8:13PM1.14m | 8:44AM1.19m | 8:54PM1.47m | 9:26AM1.59m | 9:39PM1.83m | 10:14AM1.98m | 10:37PM2.18m | 11:17AM2.31m | 11:58PM2.41m | ||||||||
5:56 | — | — | 5:58 | — | — | 6:01 | — | — | 6:01 | — | — | 6:03 | — | — | 6:05 | — | — | 6:07 | — | — | |
— | 8:46 | — | — | 8:45 | — | — | 8:43 | — | — | 8:40 | — | — | 8:37 | — | — | 8:36 | — | — | 8:34 | — | |
mm | — | — | — | — | — | — | — | 1 | 4 | — | — | 4 | 1 | — | 2 | — | — | 1 | — | — | — |
Temp °C | 14 | 16 | 15 | 15 | 15 | 16 | 15 | 15 | 18 | 17 | 17 | 15 | 15 | 17 | 16 | 15 | 15 | 14 | 14 | 15 | 14 |
Feels °C | 10 | 13 | 13 | 14 | 12 | 15 | 14 | 14 | 16 | 16 | 16 | 11 | 9 | 12 | 12 | 13 | 14 | 12 | 11 | 13 | 12 |
Swell 1 Height (m) Direction Period (s) | SW 6 | SW 6 | N 4 | — | — | — | SW 5 | SW 5 | — | SW 4 | SW 6 | — | SW 16 | NW 4 | SW 16 | SW 6 | SW 6 | SW 6 | SSW 6 | N 4 | NW 3 |
1 | 1 | 1 | — | — | — | 4 | 4 | — | 16 | 15 | — | 10 | 4 | 10 | 25 | 11 | 5 | 3 | 9 | 2 | |
Swell 2 Height (m) Direction Period (s) | W 8 | — | SW 6 | — | SW 5 | — | — | SW 5 | — | — | NW 4 | — | — | S 15 | — | SW 15 | SW 14 | SW 14 | SW 14 | SW 5 | SW 13 |
1 | — | 1 | — | 1 | — | — | 4 | — | — | 8 | — | — | 5 | — | 8 | 8 | 8 | 7 | 1 | 7 | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | SW 13 | SW 5 |
— | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 7 | 1 | |
Wind waves Height (m) Direction Period (s) | N 4 | N 4 | — | — | — | SW 4 | WNW 4 | NW 3 | SSW 4 | WNW 3 | — | W 4 | W 4 | SW 4 | SW 5 | WNW 5 | NW 4 | NNW 6 | NW 5 | WNW 4 | W 3 |
12 | 8 | — | — | — | 6 | 5 | 3 | 28 | 5 | — | 12 | 28 | 18 | 56 | 27 | 7 | 109 | 47 | 5 | 1 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 311 | 792 | 251 | 246 | 275 | 249 | 249 | 275 | 388 | 55 | 506 | 246 | 251 | 251 | 236 | 55 | 249 | 59 | 187 | 194 | 184 |
Best forecast wave conditions in Anglesy | |||||||||||||||||||||
Best forecast wave conditions in United Kingdom | |||||||||||||||||||||
Header Global | |||||||||||||||||||||
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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.











