Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 26 Aug 2026:
- Most powerful swell: Tuesday 1 Sep, 4AM (local time) - 8ft (2.4m), 7s period, SW swell with 526 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 Tuesday (Sep 01) at 4AM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.6m 5s period and expected on Friday (Aug 28) at 7AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 4AM (Tue 1st Sep) | 8ft (2.4m) 7s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
G'day, I'm Rusty. Let's be straight with you about Cable Bay (Porth Trecastell) – it's a bit of a tough stretch ahead. The 16-day window is almost entirely dominated by "poor surf conditions" and the data makes it clear: there's hardly a session worth paddling out for. The water temperature is sitting at 64°F right now, which is 4°F warmer than usual for this time of year – that's much warmer than normal, so you might not need a thick wetsuit, but the waves just aren't showing up.
The first whole week is a write-off. From Wednesday the 26th of August right through to early September, every single window is a dud. Swell heights are tiny, often under 2 ft, and the combined wave energy is weak, like 19 (weak energy) or 13 (weak energy). Wind is a mess too – cross-off or onshore – and the wave comment is "poor surf conditions" across the board. There's a tiny glimmer of offshore wind on Thursday the 27th afternoon, but with only 0.7 ft swell and 7 seconds period, it's not worth the paddle.
The second week stays grim. Around Saturday the 5th of September, we see a bit more height – 4 ft to 5 ft – but the wind is onshore or cross-off, and the energy is still moderate at best (94 for the morning, 150 for the 6th morning). The 6th of September Sunday morning at least gets a "surfable waves but very ordinary conditions" tag with a 5 ft WNW swell at 6 seconds, cross-off wind from the SE at 15 km/h, and 150 (moderate energy). That's the first real chance, but it's far from epic.
And then the real standout, if you can call it that, appears on Thursday the 10th of September. The morning sees 6 ft swell from the SW at 6 seconds, winds from the N at 10 km/h (cross-off, clean), and 293 (moderate energy). The afternoon is even better: 8 ft swell from the SW at 7 seconds, NNW wind at 10 km/h (cross-off, glassy), and 606 (strong energy). The wave comment says "expect very good surf conditions." That's the one. This is a proper groundswell (7 seconds is still short, but it's better than the 5-6 seconds we've had), and the energy is solid. The optimum swell direction for Cable Bay is SW, so this is perfectly lined up. The water temperature anomaly is still much warmer than normal, so you'll be comfortable. The break is "fairly consistent" and exposed to SW swell, so it should handle this. The wind is light and offshore, which means clean, glassy conditions. This is a decent session, but remember it's a long-range call – promising but not locked in.
If you're a beginner, the 8 ft is getting a bit big, but it's manageable. The 6 ft morning is better for intermediates. The crowd situation at Cable Bay is "sometimes," so you might have company, but it's not a zoo.
To be honest, the first 9 days are a total blank. There's a gap from Wednesday the 26th of August all the way to Saturday the 6th of September with virtually no surfable options. Then the 6th is ordinary, and the 10th is the only real standout. If you're desperate, the 6th morning might give you a paddle, but don't expect much.
Rusty.
Short Range ForecastHeavy rain (total 31mm), heaviest during Thu afternoon. Warm (max 23°C on Wed afternoon, min 16°C on Thu night). Wind will be generally light. | Days 4-6 Weather SummaryHeavy rain (total 45mm), heaviest during Sun afternoon. Very mild (max 17°C on Sat morning, min 14°C on Sun night). Winds increasing (light winds from the SSE on Sat afternoon, strong winds from the SSW by Mon night). | ||||||||||||||||||||
Wednesday 26 | Thursday 27 | Friday 28 | Saturday 29 | Sunday 30 | Monday 31 | Tuesday 1 | |||||||||||||||
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 | SSW 8 | SSW 7 | SSW 7 | SSW 7 | SSW 6 | SSW 6 | SSW 7 | SW 7 | SSW 7 | SSW 6 | SSW 8 | SW 9 | SSW 6 | SW 8 | SW 8 | SW 7 | SW 7 | SW 7 | SW 7 | NW 4 |
Wave Graph | |||||||||||||||||||||
17 | 12 | 5 | 6 | 4 | 13 | 16 | 29 | 88 | 85 | 80 | 184 | 93 | 193 | 262 | 145 | 89 | 391 | 144 | 54 | 27 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | off | cross-off | cross-off | cross-on | cross | on | cross-on | cross | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | on | on | cross-on | cross-on | cross-on |
High Tide | 9:35PM3.81m | 9:55AM3.58m | 10:04PM4.02m | 10:23AM3.73m | 10:32PM4.18m | 10:51AM3.84m | 11:00PM4.28m | 11:19AM3.92m | 11:30PM4.30m | 11:49AM3.93m | 00:03AM4.23m | 12:23PM3.87m | 00:40AM4.07m | ||||||||
Low Tide | 3:47PM0.67m | 4:13AM0.41m | 4:20PM0.46m | 4:45AM0.20m | 4:53PM0.30m | 5:18AM0.06m | 5:26PM0.21m | 5:52AM0.00m | 6:01PM0.20m | 6:27AM0.05m | 6:37PM0.27m | 7:03AM0.19m | 7:16PM0.42m | ||||||||
6:16 | — | — | 6:16 | — | — | 6:18 | — | — | 6:20 | — | — | 6:22 | — | — | 6:24 | — | — | 6:26 | — | — | |
— | 8:22 | — | — | 8:20 | — | — | 8:16 | — | — | 8:15 | — | — | 8:13 | — | — | 8:09 | — | — | 8:07 | — | |
mm | — | 1 | — | 2 | 17 | 10 | — | — | 1 | 5 | 12 | — | 3 | 15 | 1 | — | — | 9 | — | — | — |
Temp °C | 20 | 23 | 20 | 20 | 17 | 17 | 17 | 18 | 17 | 17 | 17 | 16 | 17 | 16 | 15 | 14 | 15 | 16 | 15 | 17 | 15 |
Feels °C | 19 | 23 | 18 | 20 | 16 | 17 | 15 | 16 | 16 | 15 | 17 | 13 | 14 | 11 | 10 | 8 | 10 | 10 | 9 | 12 | 10 |
Swell 1 Height (m) Direction Period (s) | NE 5 | SSW 8 | SSW 7 | SSW 7 | NE 4 | N 4 | SSW 6 | SSW 7 | N 4 | SSW 7 | SSW 6 | SSW 8 | SW 9 | — | SW 8 | SW 8 | WNW 5 | — | SW 7 | SW 7 | SW 6 |
6 | 12 | 5 | 5 | 5 | 5 | 16 | 29 | 1 | 85 | 80 | 184 | 93 | — | 262 | 145 | 19 | — | 144 | 54 | 19 | |
Swell 2 Height (m) Direction Period (s) | SW 8 | — | SSW 4 | — | SSW 7 | SSW 6 | S 12 | N 5 | — | N 4 | — | — | WNW 3 | — | — | — | NNW 5 | — | — | NW 4 | — |
17 | — | 2 | — | 4 | 13 | 3 | 15 | — | 1 | — | — | 1 | — | — | — | 9 | — | — | 11 | — | |
Swell 3 Height (m) Direction Period (s) | S 13 | S 12 | S 12 | SW 12 | S 12 | S 12 | — | NW 4 | — | — | — | — | — | — | — | — | — | — | — | — | — |
3 | 3 | 3 | 6 | 3 | 3 | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | SSE 4 | NE 5 | NE 4 | NE 5 | — | N 4 | NNW 5 | W 4 | SW 7 | SSE 4 | — | NW 3 | SSW 3 | SSW 6 | SW 7 | WNW 5 | SW 7 | SW 7 | WNW 5 | WNW 4 | NW 4 |
2 | 3 | 2 | 11 | — | 9 | 103 | 4 | 88 | 8 | — | 5 | 4 | 193 | 262 | 69 | 89 | 391 | 40 | 12 | 27 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 301 | 324 | 285 | 258 | 221 | 221 | 212 | 44 | 277 | 298 | 106 | 96 | 296 | 87 | 44 | 167 | 302 | 283 | 584 | 506 | 295 |
Best forecast wave conditions in Anglesy | |||||||||||||||||||||
Best forecast wave conditions in United Kingdom | |||||||||||||||||||||
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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.











