Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 21 Aug 2026:
- Best quality surf: Wednesday 26 Aug, 10PM (local time) - 2.5ft (0.8m), 6s period, SSW swell with cross-offshore winds.
- Most powerful swell: Thursday 27 Aug, 4AM (local time) - 3.5ft (1.1m), 6s period, SSW swell with 91 kJ wave energy.
- Next surfable swell (1★+): Wednesday 26 Aug, 10PM (local time) - 2.5ft (0.8m), 6s period with SSW swell.
Best Forecast Surf Conditions for Cable Bay (Porth Trecastell) this week:
The surf forecast for Cable Bay (Porth Trecastell) over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Wednesday (Aug 26) at 10PM. The primary swell is predicted to be 0.8m and 6s period with a secondary swell of 0.4m and 7s. Another secondary swell of 0.1m and 12s is also forecast. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Cable Bay (Porth Trecastell) in the next 16 days are 1.1m 6s and forecast to arrive on Thursday (Aug 27) at 4AM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 5s period and expected on Saturday (Aug 22) at 1AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 10PM (Wed 26th Aug) | 2.5ft (0.8m) 6s |
| Best Surf | 10PM (Wed 26th Aug) | 2.5ft (0.8m) 6s |
| Most Powerful | 4AM (Thu 27th Aug) | 3.5ft (1.1m) 6s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let's be straight with you: it's flat as a pancake out there for the next stretch. We're looking at a real drought of surf for the next couple of weeks. The ocean's just not working with us at all this period.
First off, let's talk about what we're dealing with at Cable Bay (Porth Trecastell) . The water is a balmy 65°, which is much warmer than we'd normally expect for this time of year – that's something, I guess, but it won't get you a wave.
Right now, this Friday the 21st, we've got next to nothing. We're seeing an ankle-snapper of 0.3ft with a weak energy reading of 15. The wind is a cross-offshore, so it would be clean, but there's no swell to shape. The next several days, right through the 25th, look much the same. It's a sad story of tiny 0.3ft swells and clean but empty water. The energy is just super weak, mostly single digits.
There's a little blip of life around Wednesday the 26th, the swell pushes up to 1ft in the morning with an energy of 25, and by the afternoon we see 3ft with energy jumping to 47. But the period is a very short, weak 5-8 seconds, and a cross-shore wind is going to have it all chopped up and messy. It's a tease, not a real option.
The first real, albeit tiny, chance of a surfable wave shows up on Thursday the 27th. We've got 3ft of swell at 7 seconds, and the energy bumps up to a slightly more interesting 91. The morning wind is offshore, and by the afternoon it goes glassy. That's the only time in this whole forecast where you might get a clean, rideable wave, though "ordinary" is the word that comes to mind. It's an improvement, but it's marginal.
After that, it all falls apart. The end of August and beginning of September brings in more wind and some choppy conditions, but honestly, the swell stays mostly miserable. We see a few pulses of energy – 101 on the 29th, 118 on the 30th, and a bigger 180 by the 1st of September – but the swell direction goes all over the place and the period gets short and crumbly. That bigger energy on the 1st comes with a full onshore wind, making it blown-out and unrideable. It's one of those cases where the ocean is throwing its weight around but with no shape or power for us.
The second week remains a washout. The swell fades back to 0.3ft by the 3rd and 5th of September, with light but messy cross-offshore winds. All energy readings are in the low double digits. It's just flat and uninspiring.
So, here's the bottom line: there are no standout days, no purple patches. The only day that looks like it might offer anything is the morning of Thursday the 27th, but we're talking a marginal, clean wave at best. If you're desperate, that's your window, but keep your expectations super low. This is a proper lull. But with this being a fairly consistent spot, it won't stay poor for long. Keep an eye on it – the forecasts can always change.
Stay patient.
Rusty.
Short Range ForecastLight rain (total 2mm), mostly falling on Fri morning. Very mild (max 17°C on Fri afternoon, min 13°C on Fri night). Wind will be generally light. | Days 4-6 Weather SummaryLight rain (total 6mm), mostly falling on Wed morning. Warm (max 22°C on Mon afternoon, min 14°C on Mon night). Wind will be generally light. | ||||||||||||||||||||
Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | Wednesday 26 | Thursday 27 | |||||||||||||||
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 14 | SW 13 | SW 13 | SW 15 | SW 15 | SW 15 | SW 14 | SW 14 | SW 14 | SW 14 | SW 13 | SW 13 | SW 13 | SW 13 | SSW 9 | SW 8 | SSW 5 | S 6 | SSW 7 | WNW 5 | SSW 7 |
Wave Graph | |||||||||||||||||||||
7 | 7 | 7 | 8 | 8 | 8 | 8 | 7 | 7 | 8 | 7 | 7 | 7 | 7 | 8 | 18 | 30 | 50 | 54 | 28 | 21 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-on | cross | cross-off | off | glassy | cross-off |
High Tide | 4:46PM2.83m | 5:38AM2.76m | 6:19PM2.84m | 7:04AM2.82m | 7:32PM3.02m | 8:05AM2.99m | 8:24PM3.28m | 8:49AM3.20m | 9:03PM3.55m | 9:25AM3.40m | 9:35PM3.81m | 9:55AM3.58m | 10:04PM4.02m | ||||||||
Low Tide | 10:45AM1.54m | 11:34PM1.55m | 12:20PM1.61m | 1:12AM1.48m | 1:41PM1.46m | 2:17AM1.25m | 2:33PM1.20m | 3:02AM0.96m | 3:12PM0.93m | 3:39AM0.68m | 3:47PM0.67m | 4:13AM0.41m | 4:20PM0.46m | ||||||||
6:07 | — | — | 6:09 | — | — | 6:11 | — | — | 6:11 | — | — | 6:13 | — | — | 6:16 | — | — | 6:16 | — | — | |
— | 8:32 | — | — | 8:30 | — | — | 8:29 | — | — | 8:27 | — | — | 8:23 | — | — | 8:22 | — | — | 8:20 | — | |
mm | 2 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 4 | 1 | 1 | — | 2 | 1 |
Temp °C | 15 | 17 | 14 | 13 | 14 | 14 | 16 | 17 | 17 | 20 | 22 | 19 | 19 | 20 | 18 | 17 | 20 | 19 | 20 | 19 | 17 |
Feels °C | 11 | 13 | 11 | 10 | 10 | 12 | 13 | 14 | 14 | 18 | 19 | 14 | 17 | 15 | 14 | 17 | 20 | 19 | 20 | 19 | 17 |
Swell 1 Height (m) Direction Period (s) | SW 6 | SW 6 | SW 13 | SW 15 | SW 15 | SW 15 | SW 14 | SW 14 | SW 14 | SW 10 | SW 9 | SW 9 | — | SW 8 | SSW 9 | SW 8 | SW 8 | SW 7 | SSW 7 | SSW 7 | SSW 7 |
1 | 1 | 7 | 8 | 8 | 8 | 8 | 7 | 7 | 4 | 3 | 3 | — | 3 | 8 | 18 | 17 | 13 | 54 | 28 | 21 | |
Swell 2 Height (m) Direction Period (s) | SW 14 | SW 13 | S 5 | — | — | S 12 | — | — | SW 11 | SW 14 | NE 4 | SW 13 | SW 13 | — | S 13 | NNE 4 | NE 4 | S 12 | S 12 | — | — |
7 | 7 | 1 | — | — | 3 | — | — | 5 | 8 | 1 | 7 | 7 | — | 3 | 2 | 1 | 3 | 3 | — | — | |
Swell 3 Height (m) Direction Period (s) | SW 13 | — | — | — | — | W 12 | — | — | — | — | SW 13 | — | SW 9 | SW 13 | — | S 13 | — | — | — | S 12 | — |
7 | — | — | — | — | 3 | — | — | — | — | 7 | — | 3 | 7 | — | 3 | — | — | — | 3 | — | |
Wind waves Height (m) Direction Period (s) | NNW 5 | NNW 4 | NNW 5 | NNW 5 | NNW 5 | N 5 | N 4 | N 4 | NE 2 | — | — | E 3 | NE 5 | ENE 3 | NE 5 | S 4 | SSW 5 | S 6 | WNW 4 | WNW 5 | W 4 |
48 | 20 | 28 | 32 | 23 | 16 | 5 | 2 | 1 | — | — | 6 | 7 | 6 | 17 | 4 | 30 | 50 | 34 | 25 | 14 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 185 | 284 | 180 | 172 | 284 | 211 | 211 | 295 | 158 | 256 | 259 | 259 | 286 | 258 | 260 | 290 | 187 | 0 | 0 | 0 | 244 |
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.











