Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 18 Aug 2026:
- Best quality surf: Monday 24 Aug, 10PM (local time) - 5ft (1.6m), 6s period, S swell with cross-offshore winds.
- Most powerful swell: Tuesday 25 Aug, 10AM (local time) - 4.5ft (1.4m), 8s period, SSW swell with 245 kJ wave energy.
- Next surfable swell (1★+): Monday 24 Aug, 10PM (local time) - 5ft (1.6m), 6s period with S 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 Monday (Aug 24) at 10PM. The primary swell is predicted to be 1.6m and 6s period with a secondary swell of 0.1m and 13s. 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 1.4m 8s and forecast to arrive on Tuesday (Aug 25) at 10AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.7m 6s period and expected on Thursday (Aug 20) at 1PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 10PM (Mon 24th Aug) | 5ft (1.6m) 6s |
| Best Surf | 10PM (Mon 24th Aug) | 5ft (1.6m) 6s |
| Most Powerful | 10AM (Tue 25th Aug) | 4.5ft (1.4m) 8s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright, Rusty here. Let's have a look at what's on offer for the Holy Island area.
Honestly, mate, it's a pretty grim picture for the next two weeks. We're looking at a long stretch of tiny, weak, and messy conditions. The first few days are a write-off, and it's not until the very end of the month that we get a slight glimmer of something rideable. The best bet is a long way off, so patience is key.
The first real option doesn't pop up until the morning of Saturday the 29th of August. The water temp is sitting at 63°, which is a touch warmer than normal for this time of year, so at least the rubber won't be too thick.
For that Saturday session, Trearddur Bay (Holy Island) is the only spot in the game. It's a beginner-friendly break, but it's inconsistent, so don't expect a wave every minute. The swell is only 2ft, coming from the SSW, and the combined energy is a weak 75. The period is a middling 9 seconds, so it's not a proper groundswell, but it's not a complete windswell either. The real highlight here is the wind. Saturday morning is forecast to be glassy. That's a massive positive for a spot that's usually a bit exposed to the wind. It'll be clean as a whistle, just tiny. The crowds are listed as "sometimes", so you might have a few others with the same idea, but it won't be a circus.
After that, the wind swings onshore and the tiny swell drops back to nothing for the rest of the forecast period. The 25th of August sees a pulse of energy hit 245 (moderate), with 5ft swell from the SSW and an 8-second period, but the wind is cross-shore and the quality is still rated as poor. It's a no-go for a clean surf.
So, save your energy for the 29th. It's not going to be epic, but a glassy 2ft at a beginner-friendly spot is the only thing worth paddling out for in the entire 16-day window. The rest of the time, the board's staying in the car.
Rusty.
Short Range ForecastModerate rain (total 13mm), heaviest on Thu morning. Very mild (max 17°C on Tue afternoon, min 13°C on Thu night). Winds decreasing (fresh winds from the SSW on Wed afternoon, light winds from the NNE by Thu night). | Days 4-6 Weather SummaryMostly dry. Very mild (max 15°C on Fri afternoon, min 12°C on Fri night). Wind will be generally light. | ||||||||||||||||||||
Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | |||||||||||||||
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 | WSW 4 | WSW 4 | SW 4 | SW 6 | SW 6 | SW 6 | SW 14 | SW 14 | SW 13 | SW 13 | SW 15 | SW 15 | SW 15 | SW 14 | SW 14 | SW 14 | SSW 4 | SSW 5 | S 6 |
Wave Graph  | |||||||||||||||||||||
 kJ | 32 | 21 | 21 | 25 | 20 | 47 | 16 | 8 | 8 | 7 | 7 | 7 | 8 | 8 | 8 | 8 | 7 | 8 | 22 | 54 | 243 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | on | cross-on | on | cross-on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | off | cross-on | on | cross-off |
High Tide | 2:51PM4.93m | 3:07AM4.98m | 3:32PM4.68m | 3:52AM4.62m | 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 | ||||||||
Low Tide | 8:54PM1.47m | 9:26AM1.59m | 9:39PM1.83m | 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 | ||||||||
 |  |  | |  | | | | | | |  | | | | |  |  | | | | |
 | 6:01 | — | — | 6:03 | — | — | 6:05 | — | — | 6:07 | — | — | 6:09 | — | — | 6:11 | — | — | 6:13 | — | — |
 | — | 8:40 | — | — | 8:37 | — | — | 8:36 | — | — | 8:34 | — | — | 8:31 | — | — | 8:29 | — | — | 8:27 | — |
mm | — | — | 2 | — | 1 | 5 | 4 | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 16 | 17 | 15 | 15 | 16 | 16 | 15 | 15 | 14 | 14 | 15 | 14 | 13 | 15 | 15 | 13 | 14 | 14 | 16 | 16 | 17 |
Feels °C | 12 | 14 | 11 | 11 | 11 | 13 | 11 | 10 | 10 | 11 | 12 | 9 | 10 | 11 | 12 | 10 | 11 | 12 | 13 | 13 | 15 |
Swell 1 Height (m) Direction Period (s) | SW 6 | NW 4 | — | SW 16 | NW 4 | SW 6 | SW 6 | SW 6 | N 4 | SW 6 | SW 5 | SW 13 | SW 15 | SW 15 | SW 15 | SW 14 | N 5 | N 4 | SW 14 | SW 13 | SW 13 |
| kJ | 32 | 9 | — | 10 | 1 | 47 | 16 | 6 | 15 | 1 | 1 | 7 | 8 | 8 | 8 | 8 | 19 | 1 | 8 | 7 | 7 |
Swell 2 Height (m) Direction Period (s) | — | — | — | — | S 15 | SW 16 | SW 15 | SW 14 | SW 6 | SW 14 | SW 13 | — | — | — | S 12 | — | SW 14 | SW 14 | — | — | — |
| kJ | — | — | — | — | 5 | 10 | 8 | 8 | 1 | 7 | 7 | — | — | — | 3 | — | 7 | 8 | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | SW 14 | SW 13 | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | — | — | — | — | — | — | — | 8 | 7 | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | WNW 4 | SW 6 | WSW 4 | WSW 4 | SW 4 | WNW 3 | NNW 4 | N 6 | — | NNW 4 | NNW 4 | N 3 | NNW 4 | NNW 4 | N 4 | NNW 5 | WNW 3 | WSW 2 | SSW 4 | SSW 5 | S 6 |
| kJ | 24 | 21 | 21 | 25 | 20 | 4 | 39 | 110 | — | 15 | 10 | 1 | 14 | 9 | 9 | 25 | 2 | 1 | 22 | 54 | 243 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 51 | 376 | 192 | 192 | 246 | 51 | 179 | 179 | 179 | 179 | 284 | 253 | 241 | 284 | 267 | 184 | 358 | 273 | 280 | 249 | 0 |
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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