Surf Forecasts:
Trearddur Bay (Holy Island) surf forecast from 9 Sep 2026:
- Best quality surf: Wednesday 16 Sep, 7PM (local time) - 6ft (1.9m), 6s period, NW swell with offshore winds.
- Most powerful swell: Thursday 10 Sep, 4PM (local time) - 7ft (2.2m), 7s period, SSW swell with 424 kJ wave energy.
- Next surfable swell (1★+): Wednesday 16 Sep, 1PM (local time) - 5ft (1.5m), 5s period with WNW 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 (Sep 16) at 1PM. The primary swell is predicted to be 1.5m and 5s period with a secondary swell of 0.8m and 7s. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Trearddur Bay (Holy Island) in the next 16 days are 2.2m 7s and forecast to arrive on Thursday (Sep 10) at 4PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 5s period and expected on Sunday (Sep 13) at 7AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 1PM (Wed 16th Sep) | 5ft (1.5m) 5s |
| Best Surf | 7PM (Wed 16th Sep) | 6ft (1.9m) 6s |
| Most Powerful | 4PM (Thu 10th Sep) | 7ft (2.2m) 7s |
Table - best surf conditions forecast for Trearddur Bay (Holy Island) over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let's take a look at what Trearddur Bay (Holy Island) has in store for us over the next couple of weeks.
Honestly, the outlook is a bit of a struggle for most of this run. We've got a long gap of flat or poor conditions stretching from now all the way through the first week. You’re looking at small, weak swells and a lot of onshore or cross-shore wind messing things up. The first real sniff of anything happens deep into the second week.
Wednesday the 23rd is the only session that really stands out. After all that grovel and wind, we get a clean window on Wednesday morning. The swell ticks up to a surfable 4.6ft from the SW. It’s not huge, but the wind turns light and offshore from the ESE, cleaning it right up. You'll have clean, lined-up little waves to yourself, which at a spot that's *inconsistent*, is a proper treat. The water temp is sitting at 62.4°F, which is a touch warmer than normal for this time of year, so the shorty will do. Keep in mind, with a combined swell energy of 106, it's moderate energy, not a ton of punch, but it's the best and really the only playable option in the whole two weeks.
Even the 16th of September has some offshore wind, but with a 6.6ft swell and onshore winds the rest of the time, it’s too big and unruly for a spot like Trearddur Bay in that wind. The rest is a write-off of poor surf conditions or next to nothing.
Given the lack of any consistent, quality swell, this is one of those times you just have to sit it out. Forecasts can always change, but right now, the 23rd morning is the one to circle.
Short Range ForecastLight rain (total 6mm), mostly falling on Thu afternoon. Very mild (max 17°C on Thu afternoon, min 13°C on Thu night). Winds decreasing (strong winds from the SSW on Thu morning, light winds from the SW by Fri afternoon). | Days 4-6 Weather SummaryLight rain (total 7mm), mostly falling on Sat morning. Warm (max 20°C on Sat afternoon, min 13°C on Sat night). Winds decreasing (strong winds from the SW on Sat morning, light winds from the N by Sat night). | ||||||||||||||||||||
Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | Sunday 13 | Monday 14 | Tuesday 15 | |||||||||||||||
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 8 | SW 8 | SW 4 | SSW 6 | SSW 7 | SW 7 | SW 7 | SW 6 | SSW 5 | SW 6 | SSW 6 | SSW 6 | SSW 6 | SW 6 | SSW 6 | SSW 5 | SSW 5 | SW 6 | SSW 5 | SSW 5 | SSW 6 |
Wave Graph  | |||||||||||||||||||||
 kJ | 15 | 14 | 26 | 163 | 424 | 103 | 35 | 20 | 80 | 269 | 216 | 71 | 26 | 9 | 12 | 56 | 64 | 123 | 64 | 41 | 91 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross | cross-on | cross-on | cross-on | cross-on | cross | on | cross-on | on | on | cross-off | cross | on | cross-on | cross-on | on | cross-on | cross-on | on | cross-off |
High Tide | 10:08PM5.63m | 10:36AM5.47m | 10:49PM5.85m | 11:14AM5.59m | 11:28PM5.95m | 11:50AM5.61m | 00:04AM5.91m | 12:25PM5.56m | 00:40AM5.77m | 1:00PM5.44m | 1:15AM5.55m | 1:34PM5.27m | 1:50AM5.26m | ||||||||
Low Tide | 3:50PM1.24m | 4:19AM0.68m | 4:32PM0.95m | 5:00AM0.47m | 5:11PM0.75m | 5:39AM0.42m | 5:49PM0.68m | 6:16AM0.50m | 6:26PM0.74m | 6:52AM0.70m | 7:02PM0.91m | 7:27AM0.99m | 7:38PM1.17m | ||||||||
 |  |  |  | |  | | | | |  | | | |  | | | | |  |  | |
 | 6:39 | — | — | 6:41 | — | — | 6:43 | — | — | 6:45 | — | — | 6:47 | — | — | 6:48 | — | — | 6:50 | — | — |
 | — | 7:50 | — | — | 7:46 | — | — | 7:45 | — | — | 7:42 | — | — | 7:39 | — | — | 7:37 | — | — | 7:35 | — |
mm | — | — | — | 1 | 3 | 1 | — | — | 1 | 6 | — | — | — | — | — | 1 | — | — | — | 1 | 13 |
Temp °C | 14 | 14 | 15 | 16 | 17 | 17 | 13 | 14 | 16 | 16 | 20 | 17 | 14 | 14 | 17 | 17 | 18 | 17 | 17 | 19 | 14 |
Feels °C | 10 | 12 | 9 | 9 | 14 | 13 | 9 | 10 | 9 | 10 | 18 | 16 | 12 | 13 | 15 | 13 | 13 | 13 | 14 | 19 | 10 |
Swell 1 Height (m) Direction Period (s) | SW 8 | N 5 | N 4 | — | — | SW 7 | SW 7 | SW 6 | — | — | — | SSW 6 | SSW 6 | SW 6 | N 4 | — | — | SW 12 | — | — | SSW 6 |
| kJ | 15 | 19 | 1 | — | — | 103 | 35 | 20 | — | — | — | 71 | 26 | 9 | 1 | — | — | 6 | — | — | 91 |
Swell 2 Height (m) Direction Period (s) | SW 6 | SW 8 | — | — | — | — | — | NNW 4 | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | 5 | 14 | — | — | — | — | — | 3 | — | — | — | — | — | — | — | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | NW 4 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | NNW 6 | W 4 | SW 4 | SSW 6 | SSW 7 | WNW 4 | NW 4 | WNW 3 | SSW 5 | SW 6 | SSW 6 | NNW 3 | N 5 | N 4 | SSW 6 | SSW 5 | SSW 5 | SW 6 | SSW 5 | SSW 5 | — |
| kJ | 111 | 4 | 26 | 163 | 424 | 7 | 18 | 2 | 80 | 269 | 216 | 4 | 32 | 10 | 12 | 56 | 64 | 123 | 64 | 41 | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 179 | 51 | 179 | 312 | 480 | 51 | 179 | 187 | 283 | 251 | 236 | 8 | 161 | 155 | 186 | 246 | 278 | 238 | 186 | 51 | 59 |
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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