Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 16 Sep 2026:
- Most powerful swell: Friday 18 Sep, 7PM (local time) - 8ft (2.4m), 7s period, SW swell with 563 kJ wave energy.
Best Forecast Surf Conditions for Cable Bay (Porth Trecastell) this week:
The most powerful waves expected at Cable Bay (Porth Trecastell) in the next 16 days are 2.4m 7s and forecast to arrive on Friday (Sep 18) at 7PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.3m 5s period and expected on Wednesday (Sep 16) at 4AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 7PM (Fri 18th Sep) | 8ft (2.4m) 7s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Alright, mate, Rusty here. Let's have a look at what's cookin' for Cable Bay over the next couple of weeks. I gotta be straight with you – it's lookin' grim for a proper paddle. The whole sixteen-day window is a tough sell, with no real standout sessions for a surfer.
The pattern is pretty bleak. We've got a run of poor surf conditions that just won't let up. The first recommendation... well, there isn't really one that gets a nod. The whole first week is a write-off. From Tuesday the 15th right through to Sunday the 20th, it's messy. The winds are mostly cross-onshore and strong, between 12 and 22 mph, making everything choppy and lumpy. The swell energy is weak, mostly under 100, and at its highest on Thursday the 17th it only reaches 188 (moderate energy), but the strong wind just ruins it. The swell height does get up to 6 ft on that Thursday, but with 19-22 mph winds, it's just a washing machine.
The water temp is 62°F which is a touch warmer than normal for this time of year, which is nice for the skin, but you won't be feeling it through a wetsuit hood as you stare at the chop.
After that, from Monday the 21st of September through to Wednesday the 30th, the swell just drops right off. We're talking tiny waves, less than 2 ft for most of it, and the energy is pitiful – often single digits. There are a few glassy moments on the mornings of the 22nd and 27th of September, but with 0.3 ft of swell, it's a lake, not a surf break. The swell direction is all over the shop – SW, S, SSE – with the only consistency being there's no power behind it.
The only whisper of something is on the afternoon of Tuesday the 24th of September. The swell bumps up to 5 ft from the WSW, with a bit more energy (113), and the wind goes cross-off from the NNW at 19 mph. That's "clean" conditions. But even then, the period is a short 5 seconds, so it'll be weak and crumbly. For a local spot that's exposed to SW swells, it's just not enough to get excited about.
To be honest, for the first week here with that onshore wind and a bit of size, the beach setup might look more appealing to the kite surfers than anyone on a paddle board.
Look, it's a blank run. The area can be like this sometimes. Forecasts can change, but right now, I'd save the wax.
Rusty.
Short Range ForecastLight rain (total 5mm), mostly falling on Tue afternoon. Very mild (max 16°C on Tue afternoon, min 13°C on Tue night). Mainly fresh winds. | Days 5-7 Weather SummaryLight rain (total 6mm), mostly falling on Fri afternoon. Very mild (max 18°C on Sun night, min 12°C on Sat night). Winds decreasing (strong winds from the SSW on Fri afternoon, light winds from the WSW by Mon morning). | |||||||||||||||||||
Tue 15 | Wednesday 16 | Thursday 17 | Friday 18 | Saturday 19 | Sunday 20 | Monday 21 | ||||||||||||||
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 5 | SW 6 | NW 5 | W 4 | SW 5 | WSW 6 | W 6 | W 6 | WSW 5 | SW 6 | SW 7 | SW 7 | SW 7 | SW 7 | SSW 6 | SW 5 | SW 5 | SW 5 | SW 4 | SSW 2 |
Wave Graph  | ||||||||||||||||||||
 kJ | 85 | 13 | 68 | 18 | 141 | 188 | 180 | 133 | 82 | 326 | 248 | 301 | 135 | 46 | 26 | 49 | 53 | 10 | 5 | 1 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross | cross | cross-on | on | cross-on | cross-on | cross-on | on | on | on | cross-on | cross-on | cross-on | on | cross-on | on | on | on | cross-on |
High Tide | 00:44AM3.84m | 1:00PM3.60m | 1:24AM3.48m | 1:40PM3.31m | 2:09AM3.11m | 2:30PM3.01m | 3:16AM2.79m | 3:54PM2.78m | 5:10AM2.63m | 5:52PM2.79m | 6:48AM2.73m | 7:09PM3.00m | ||||||||
Low Tide | 7:12PM0.44m | 7:33AM0.66m | 7:49PM0.75m | 8:09AM1.03m | 8:30PM1.08m | 8:52AM1.36m | 9:24PM1.38m | 9:52AM1.62m | 10:46PM1.58m | 11:27AM1.71m | 00:33AM1.54m | 1:01PM1.56m | 1:44AM1.28m | |||||||
 |  |  | | | |  |  | |  | | | |  | | | | |  | | |
 | — | — | 6:52 | — | — | 6:54 | — | — | 6:54 | — | — | 6:56 | — | — | 6:58 | — | — | 7:01 | — | — |
 | 7:35 | — | — | 7:31 | — | — | 7:30 | — | — | 7:27 | — | — | 7:24 | — | — | 7:22 | — | — | 7:20 | — |
mm | 2 | 1 | — | — | 2 | — | — | — | — | 6 | — | — | — | — | — | — | — | — | — | — |
Temp °C | 16 | 15 | 14 | 16 | 15 | 14 | 15 | 14 | 15 | 16 | 17 | 16 | 17 | 15 | 13 | 15 | 18 | 17 | 18 | 18 |
Feels °C | 11 | 10 | 9 | 10 | 9 | 7 | 9 | 7 | 9 | 10 | 12 | 11 | 13 | 11 | 11 | 12 | 17 | 17 | 18 | 18 |
Swell 1 Height (m) Direction Period (s) | — | SW 6 | SW 6 | N 5 | — | — | — | — | — | — | — | — | — | SW 7 | NW 4 | NW 4 | — | SW 5 | SW 4 | — |
| kJ | — | 13 | 6 | 12 | — | — | — | — | — | — | — | — | — | 46 | 13 | 1 | — | 10 | 5 | — |
Swell 2 Height (m) Direction Period (s) | — | SW 11 | SW 11 | W 11 | — | — | — | — | — | — | — | — | — | — | S 14 | SW 14 | — | — | — | — |
| kJ | — | 5 | 5 | 2 | — | — | — | — | — | — | — | — | — | — | 4 | 8 | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | S 13 | S 13 | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 3 | 3 | — |
Wind waves Height (m) Direction Period (s) | W 5 | NW 5 | NW 5 | W 4 | SW 5 | WSW 6 | W 6 | W 6 | WSW 5 | SW 6 | SW 7 | SW 7 | SW 7 | WNW 5 | SSW 6 | SW 5 | SW 5 | — | — | SSW 2 |
| kJ | 85 | 61 | 68 | 18 | 141 | 188 | 180 | 133 | 82 | 326 | 248 | 301 | 135 | 33 | 26 | 49 | 53 | — | — | 1 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 618 | 172 | 173 | 261 | 283 | 284 | 541 | 187 | 261 | 506 | 506 | 283 | 44 | 44 | 44 | 256 | 256 | 180 | 244 | 178 |
Best forecast wave conditions in Anglesy | ||||||||||||||||||||
Best forecast wave conditions in United Kingdom | ||||||||||||||||||||
Header Global | ||||||||||||||||||||
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Information about the Cable Bay (Porth Trecastell) Surf forecast
The above surf forecast table for Cable Bay (Porth Trecastell) provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Cable Bay (Porth Trecastell) can be found by selecting the local surf guide option on the grey menu. Our Cable Bay (Porth Trecastell) 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 (Cable Bay (Porth Trecastell)) 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 Cable Bay (Porth Trecastell) 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 Cable Bay, camping, hotels and holiday cottages in Anglesy, consider staying in Anglesey 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 Holyhead which is 14 km (9 miles) away, Bangor, Porthmadog and Llandudno.
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