Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 20 Aug 2026:
- Best quality surf: Wednesday 26 Aug, 7PM (local time) - 3ft (0.9m), 6s period, SSW swell with glassy winds.
- Most powerful swell: Wednesday 26 Aug, 10PM (local time) - 2.5ft (0.8m), 7s period, SSW swell with 64 kJ wave energy.
- Next surfable swell (1★+): Wednesday 26 Aug, 7PM (local time) - 3ft (0.9m), 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 7PM. The primary swell is predicted to be 0.9m and 6s period with a secondary swell of 0.3m and 8s. Another secondary swell of 0.1m and 12s is also forecast. 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 0.8m 7s and forecast to arrive on Wednesday (Aug 26) at 10PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 5s period and expected on Thursday (Aug 20) at 4PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 7PM (Wed 26th Aug) | 3ft (0.9m) 6s |
| Best Surf | 7PM (Wed 26th Aug) | 3ft (0.9m) 6s |
| Most Powerful | 10PM (Wed 26th Aug) | 2.5ft (0.8m) 7s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Listen up, it's Rusty. Let's break down the next 16 days for Cable Bay.
Honestly, it's a rough patch overall. The water temp is 65°F, which is much warmer than usual for this time of year, so at least it's comfortable for a float.
The first week is a total bust. From Thursday the 20th right through to about Tuesday the 26th of August, we're looking at flat, tiny waves. The swell energy is in the teens to twenties—basically nothing. Don't bother.
Things try to pick up from Wednesday the 26th, but the wind goes onshore and ruins it. We get a little pulse of energy by the 28th, with swell heights around 5ft, but it's lumpy and cross-onshore. That's more of a kite-surfing crew's day.
The biggest swell shows up at the end of August and start of September, but it's always blown out. On the 29th of August, there's a 6ft SW swell with a decent energy reading of 291, but it's onshore. On the 2nd of September, we see a 7ft NW swell with a massive 412 energy reading, but it's cross-shore and choppy. That's big enough for experts only, but the quality is poor.
The only real window of opportunity is at the very end. On Friday the 4th of September, the wind finally cleans up. We get a moderate NNW cross-off breeze and a 3ft SSW swell with an 8-second period. The energy is moderate at 128. It's not pumping, but after all that flatness and wind, clean 3ft waves at Cable Bay are the best we've got. The swell direction is a good match for the spot, too.
So, save your energy for the 4th of September. That's your one shot.
Rusty.
Short Range ForecastLight rain (total 6mm), mostly falling on Thu morning. Very mild (max 16°C on Fri afternoon, min 12°C on Fri night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 23°C on Tue afternoon, min 14°C on Mon night). Wind will be generally light. | ||||||||||||||||||||
Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | Wednesday 26 | |||||||||||||||
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 6 | SW 6 | SW 14 | 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 | SW 13 | S 4 | SSW 6 | SSW 7 |
Wave Graph  | |||||||||||||||||||||
 kJ | 16 | 10 | 8 | 7 | 7 | 7 | 8 | 8 | 8 | 8 | 7 | 8 | 8 | 7 | 7 | 7 | 7 | 7 | 15 | 58 | 56 |
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 | off | cross-off | cross-off | off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-on | off |
High Tide | 3:26PM3.00m | 4:05AM2.90m | 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 | ||||||||
Low Tide | 10:08PM1.38m | 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 | |||||||||
 |  |  |  |  | | | | | | | | | |  | | |  | | |  | |
 | 6:05 | — | — | 6:07 | — | — | 6:09 | — | — | 6:11 | — | — | 6:11 | — | — | 6:13 | — | — | 6:16 | — | — |
 | — | 8:36 | — | — | 8:32 | — | — | 8:30 | — | — | 8:29 | — | — | 8:27 | — | — | 8:23 | — | — | 8:22 | — |
mm | 4 | — | — | 2 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 4 | 1 | 13 |
Temp °C | 15 | 15 | 14 | 15 | 16 | 14 | 14 | 15 | 15 | 15 | 16 | 16 | 21 | 22 | 20 | 21 | 23 | 21 | 18 | 20 | 17 |
Feels °C | 11 | 10 | 10 | 13 | 12 | 11 | 11 | 13 | 13 | 14 | 14 | 14 | 20 | 20 | 14 | 16 | 21 | 17 | 16 | 18 | 17 |
Swell 1 Height (m) Direction Period (s) | SW 6 | SW 6 | SSW 6 | NNW 5 | W 4 | SW 13 | SW 15 | NNW 5 | NNW 5 | N 4 | N 4 | SW 14 | SW 14 | SW 13 | SW 13 | SSE 4 | NE 5 | NE 4 | SSW 8 | SSW 8 | SSW 7 |
| kJ | 16 | 10 | 3 | 28 | 1 | 7 | 8 | 20 | 7 | 3 | 1 | 8 | 8 | 7 | 7 | 2 | 7 | 1 | 6 | 6 | 56 |
Swell 2 Height (m) Direction Period (s) | SW 15 | SW 14 | SW 14 | SW 6 | SW 6 | — | — | SW 15 | SW 15 | SW 14 | SW 14 | — | SW 9 | — | SW 8 | SW 13 | SW 13 | SW 8 | NE 4 | S 12 | S 12 |
| kJ | 8 | 8 | 8 | 1 | 1 | — | — | 8 | 8 | 8 | 7 | — | 3 | — | 3 | 7 | 7 | 2 | 1 | 3 | 3 |
Swell 3 Height (m) Direction Period (s) | — | — | — | SW 14 | SW 13 | — | — | — | S 12 | — | — | SW 11 | — | SW 8 | — | SW 8 | — | SW 13 | S 12 | — | — |
| kJ | — | — | — | 7 | 7 | — | — | — | 3 | — | — | 4 | — | 3 | — | 3 | — | 7 | 3 | — | — |
Wind waves Height (m) Direction Period (s) | NNW 4 | N 5 | NNW 5 | NNW 5 | NNW 4 | NNW 5 | NNW 5 | — | — | — | — | — | — | — | ENE 3 | ENE 5 | — | S 2 | S 4 | SSW 6 | — |
| kJ | 26 | 62 | 64 | 50 | 7 | 32 | 26 | — | — | — | — | — | — | — | 2 | 11 | — | 1 | 15 | 58 | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 167 | 830 | 185 | 47 | 284 | 187 | 233 | 284 | 158 | 211 | 302 | 158 | 256 | 258 | 258 | 386 | 322 | 260 | 296 | 179 | 0 |
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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