Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 24 Aug 2026:
- Best quality surf: Thursday 27 Aug, 10PM (local time) - 3ft (0.9m), 7s period, S swell with glassy winds.
- Most powerful swell: Sunday 30 Aug, 7PM (local time) - 7ft (2.2m), 7s period, SSW swell with 458 kJ wave energy.
- Next surfable swell (1★+): Thursday 27 Aug, 10PM (local time) - 3ft (0.9m), 7s period with S 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 Thursday (Aug 27) at 10PM. The primary swell is predicted to be 0.9m and 7s period with a secondary swell of 0.5m and 7s. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Cable Bay (Porth Trecastell) in the next 16 days are 2.2m 7s and forecast to arrive on Sunday (Aug 30) at 7PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 4s period and expected on Friday (Aug 28) at 4PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 10PM (Thu 27th Aug) | 3ft (0.9m) 7s |
| Best Surf | 10PM (Thu 27th Aug) | 3ft (0.9m) 7s |
| Most Powerful | 7PM (Sun 30th Aug) | 7ft (2.2m) 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 what’s on offer for us here.
It’s a pretty bleak stretch ahead for the most part, I’m not going to sugar-coat it. We’ve got a long run of days where the swell is tiny or the wind is just wrecking any chance of a decent wave. You’ll be looking at a lot of flat, choppy, or onshore slop, especially through this week and into the start of September. The water temp is sitting at 64°F, which is a touch warmer than normal for the time of year, so at least it won’t be freezing while you’re staring at the ocean.
The only real interest pops up around the morning of Wednesday, September 3rd down at Cable Bay (Porth Trecastell). The wind drops to dead calm, glassy conditions, with a tiny 2ft swell from the SW. The combined energy is weak at 67, so it’s not going to have any punch, but if you’ve got a soft-top or a longboard, and you just need to get wet, it’s the cleanest window we’ve got. For a more experienced surfer, it’ll be frustratingly small. The following morning, Saturday, September 5th, also has a glassy moment with 4ft from the WSW, but the energy is even weaker at 59 and the period is short (5 seconds), so again, it’s very ordinary.
Really, that Wednesday the 3rd morning is the one and only standout, and even then, it’s for the quiet, clean conditions rather than any proper swell. The rest of the 16 days is a write-off for paddle surfing. The strong cross-onshore winds and messy seas towards the end of the first week and into the second week look more interesting for kite surfing than anything with a paddle.
Rusty.
Short Range ForecastLight rain (total 9mm), mostly falling on Tue night. Warm (max 21°C on Mon afternoon, min 13°C on Mon night). Wind will be generally light. | Days 4-6 Weather SummaryHeavy rain (total 21mm), heaviest during Sat morning. Warm (max 20°C on Thu afternoon, min 15°C on Fri night). Wind will be generally light. | ||||||||||||||||||||
Monday 24 | Tuesday 25 | Wednesday 26 | Thursday 27 | Friday 28 | Saturday 29 | Sunday 30 | |||||||||||||||
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 13 | SW 13 | SSW 8 | SSW 8 | SSW 8 | SSW 7 | SSW 7 | SSW 7 | SSW 7 | SSW 7 | SSW 7 | SW 7 | SSW 6 | SSW 6 | SW 8 | SSW 8 | SSW 6 | WSW 6 |
Wave Graph  | |||||||||||||||||||||
 kJ | 8 | 7 | 7 | 7 | 7 | 7 | 13 | 12 | 5 | 6 | 4 | 111 | 71 | 30 | 14 | 4 | 117 | 129 | 158 | 275 | 361 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | off | cross-off | cross-off | cross-off | cross-off | cross-off | cross | off | off | on | cross-off | cross | cross | cross-on | cross-on | on | on | cross-on | cross-on | on |
High Tide | 8:24PM3.28m | 8:49AM3.20m | 9:03PM3.55m | 9:25AM3.40m | 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 | ||||||||
Low Tide | 2:33PM1.20m | 3:02AM0.96m | 3:12PM0.93m | 3:39AM0.68m | 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 | ||||||||
 | |  |  | |  |  |  |  | | |  | | | |  |  | | |  |  | |
 | 6:11 | — | — | 6:13 | — | — | 6:16 | — | — | 6:16 | — | — | 6:18 | — | — | 6:20 | — | — | 6:22 | — | — |
 | — | 8:27 | — | — | 8:23 | — | — | 8:22 | — | — | 8:20 | — | — | 8:16 | — | — | 8:15 | — | — | 8:13 | — |
mm | — | — | — | — | — | 5 | — | 1 | 3 | 4 | 1 | — | — | — | — | 11 | 4 | 1 | 1 | 5 | 5 |
Temp °C | 19 | 21 | 19 | 19 | 19 | 19 | 19 | 20 | 18 | 19 | 20 | 17 | 17 | 17 | 17 | 15 | 17 | 16 | 17 | 16 | 15 |
Feels °C | 17 | 18 | 14 | 17 | 17 | 14 | 19 | 20 | 17 | 18 | 20 | 18 | 16 | 15 | 15 | 12 | 16 | 13 | 12 | 11 | 9 |
Swell 1 Height (m) Direction Period (s) | SW 10 | SW 9 | SW 13 | SW 13 | SW 13 | SSW 8 | NE 5 | SSW 8 | SSW 7 | SSW 7 | NNE 4 | SSW 7 | SSW 7 | SSW 7 | NNW 5 | NNW 5 | SSW 6 | NNW 4 | — | — | — |
| kJ | 4 | 3 | 7 | 7 | 7 | 7 | 6 | 12 | 5 | 5 | 3 | 111 | 71 | 30 | 26 | 7 | 117 | 2 | — | — | — |
Swell 2 Height (m) Direction Period (s) | SW 14 | — | SW 9 | — | — | S 13 | SSW 8 | NNE 4 | — | — | SSW 7 | N 3 | — | — | SW 7 | SSW 6 | — | NNW 4 | — | — | — |
| kJ | 8 | — | 3 | — | — | 3 | 13 | 2 | — | — | 4 | 1 | — | — | 12 | 4 | — | 3 | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | SW 13 | — | SW 8 | SW 8 | — | S 12 | S 3 | S 12 | SW 12 | S 12 | — | — | — | S 11 | WNW 3 | — | — | — | — | — |
| kJ | — | 7 | — | 3 | 3 | — | 3 | 1 | 3 | 6 | 3 | — | — | — | 2 | 1 | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | — | NE 4 | E 3 | ENE 5 | NE 5 | ENE 4 | SE 4 | — | NNE 4 | NE 5 | — | — | N 4 | NW 4 | W 4 | SSW 2 | N 3 | SW 8 | SSW 8 | SSW 6 | WSW 6 |
| kJ | — | 1 | 7 | 13 | 12 | 21 | 1 | — | 2 | 5 | — | — | 10 | 45 | 14 | 1 | 8 | 129 | 158 | 275 | 361 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 256 | 259 | 256 | 261 | 258 | 233 | 246 | 300 | 285 | 285 | 258 | 0 | 96 | 277 | 261 | 259 | 44 | 297 | 285 | 297 | 261 |
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.
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