Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 1 Sep 2026:
- Most powerful swell: Thursday 3 Sep, 1AM (local time) - 5.5ft (1.7m), 7s period, SW swell with 253 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 1.7m 7s and forecast to arrive on Thursday (Sep 03) at 1AM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.4m 5s period and expected on Saturday (Sep 05) at 10AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 1AM (Thu 3rd Sep) | 5.5ft (1.7m) 7s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Right then, let's have a look at Cable Bay, or as we know it, Porth Trecastell. Gotta be honest with you, looking down the barrel of the next sixteen days, and it's a grim picture. The entire run is a write-off for any decent surf. We're staring at a solid two weeks with nothing worth paddling out for, so if you're itching for a wave, you might as well save the petrol.
The swell is on offer, but it's all junk. For the first ten days, it's a mess of short-period, wind-whipped slop. There's a bit of energy on the 2nd of September with combined energy hitting 122 (moderate), but that's pinned to a brutal 19 km/h cross-onshore wind, turning everything into a lumpy, blown-out disaster. The 8th and 9th see the biggest numbers, with swell piling up to 7 ft and 8 ft and energy readings of 437 and 468 (strong), but again, it's all under a strong, messy onshore breeze. For those days, honestly, the setup looks more interesting for kite surfing than paddle surfing; it's way too gnarly for a surfboard.
Even the back half of the forecast doesn't offer a silver lining. We get some clean, glassy conditions on the morning of the 11th of September, with a light offshore wind, but the swell is only 4 ft from the SSW with a short period of 7 seconds. The afternoon is a bit better, with a clean 5 ft swell from the SW (energy 377), but that's about as good as it gets, and it's still a "surfable but ordinary" score. The rest of the days after that just fade away into tiny, weak dribble.
For a spot that's fairly consistent, this is a shocking blank run. It just goes to show, even the exposed west-facing reefs can have their dry spells. The water temp is about average for the time of year, so no extra help there. We'll have to wait for the next weather change to breathe some life back into this wave.
Rusty.
Short Range ForecastModerate rain (total 10mm), heaviest on Wed morning. Very mild (max 19°C on Wed night, min 15°C on Mon night). Winds increasing (light winds from the W on Mon night, strong winds from the SSW by Thu afternoon). | Days 4-6 Weather SummaryLight rain (total 9mm), mostly falling on Thu night. Very mild (max 18°C on Sun afternoon, min 13°C on Fri night). Mainly fresh winds. | ||||||||||||||||||||
Tuesday 1 | Wednesday 2 | Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | |||||||||||||||
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 4 | SSW 5 | SW 5 | SSW 5 | SSW 6 | SW 7 | SW 6 | SW 5 | SSW 6 | WSW 5 | WSW 5 | NW 5 | SW 6 | SW 3 | SSW 3 | SSW 4 | SSW 5 | SW 5 | SSW 6 | SSW 5 | SW 3 |
Wave Graph  | |||||||||||||||||||||
 kJ | 21 | 59 | 27 | 117 | 218 | 253 | 116 | 76 | 109 | 123 | 80 | 43 | 8 | 7 | 9 | 36 | 32 | 62 | 18 | 6 | 5 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | on | on | cross-on | cross-on | cross-on | on | on | on | cross-on | cross-on | cross-on | cross-on | cross-on | on | cross-on | cross-on | cross-on | cross-on | on | cross | cross-on |
High Tide | 12:23PM3.87m | 00:40AM4.07m | 1:01PM3.73m | 1:22AM3.82m | 1:47PM3.51m | 2:14AM3.50m | 2:44PM3.26m | 3:24AM3.18m | 4:06PM3.08m | 5:04AM3.02m | 5:48PM3.13m | 6:46AM3.12m | 7:12PM3.41m | ||||||||
Low Tide | 7:03AM0.19m | 7:16PM0.42m | 7:43AM0.43m | 7:59PM0.63m | 8:28AM0.72m | 8:50PM0.88m | 9:25AM1.02m | 9:57PM1.11m | 10:40AM1.25m | 11:26PM1.19m | 12:11PM1.26m | 00:57AM0.99m | 1:29PM1.03m | 2:07AM0.62m | |||||||
 |  |  |  | |  | |  |  | |  |  | | |  | | | | | | | |
 | 6:26 | — | — | 6:28 | — | — | 6:30 | — | — | 6:31 | — | — | 6:33 | — | — | 6:35 | — | — | 6:35 | — | — |
 | — | 8:07 | — | — | 8:06 | — | — | 8:02 | — | — | 8:00 | — | — | 7:59 | — | — | 7:55 | — | — | 7:53 | — |
mm | — | 1 | 1 | 7 | — | 1 | — | — | 9 | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 16 | 18 | 16 | 16 | 18 | 19 | 18 | 17 | 15 | 15 | 17 | 15 | 14 | 15 | 14 | 16 | 18 | 18 | 18 | 17 | 16 |
Feels °C | 12 | 13 | 15 | 11 | 14 | 16 | 14 | 12 | 12 | 8 | 10 | 9 | 11 | 12 | 11 | 11 | 14 | 13 | 16 | 18 | 15 |
Swell 1 Height (m) Direction Period (s) | — | — | SW 5 | W 16 | SW 16 | SW 15 | SW 14 | SW 14 | SSW 6 | SW 14 | SW 14 | SSW 6 | NNW 5 | NNW 4 | SW 13 | SW 13 | SW 13 | SW 12 | SSW 6 | SSW 5 | SW 11 |
| kJ | — | — | 27 | 5 | 10 | 9 | 8 | 8 | 109 | 8 | 8 | 24 | 7 | 2 | 7 | 7 | 6 | 6 | 18 | 5 | 5 |
Swell 2 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | SW 14 | — | — | SW 14 | SW 6 | WNW 4 | — | — | — | — | SW 12 | N 4 | — |
| kJ | — | — | — | — | — | — | — | — | 8 | — | — | 8 | 8 | 1 | — | — | — | — | 6 | 1 | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | SW 14 | SW 13 | — | — | — | — | SW 12 | SW 12 | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | 7 | 7 | — | — | — | — | 5 | 6 | — |
Wind waves Height (m) Direction Period (s) | SW 4 | SSW 5 | — | SSW 5 | SSW 6 | SW 7 | SW 6 | SW 5 | WNW 4 | WSW 5 | WSW 5 | NW 5 | WNW 4 | SW 3 | SSW 3 | SSW 4 | SSW 5 | SW 5 | NW 4 | WNW 3 | SW 3 |
| kJ | 21 | 59 | — | 117 | 218 | 253 | 116 | 76 | 11 | 123 | 80 | 43 | 5 | 4 | 9 | 36 | 32 | 62 | 9 | 2 | 5 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 293 | 313 | 256 | 259 | 256 | 297 | 290 | 333 | 44 | 541 | 541 | 318 | 187 | 283 | 172 | 246 | 233 | 181 | 173 | 173 | 73 |
Best forecast wave conditions in Anglesy | |||||||||||||||||||||
Best forecast wave conditions in United Kingdom | |||||||||||||||||||||
Header Global | |||||||||||||||||||||
- Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)- Wind Speed (km/h)
FREE! Surf-Forecast.com widget for your website
The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Cable Bay (Porth Trecastell) surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.
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.
Nearest