Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 15 Aug 2026:
- Best quality surf: Thursday 20 Aug, 10PM (local time) - 3.5ft (1.0m), 5s period, NW swell with cross-offshore winds.
- Most powerful swell: Thursday 20 Aug, 10AM (local time) - 5.5ft (1.7m), 6s period, WSW swell with 201 kJ wave energy.
- Next surfable swell (1★+): Thursday 20 Aug, 10PM (local time) - 3.5ft (1.0m), 5s period with NW 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 20) at 10PM. The primary swell is predicted to be 1.0m and 5s period with a secondary swell of 0.6m and 6s. Another secondary swell of 0.1m and 14s 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 1.7m 6s and forecast to arrive on Thursday (Aug 20) at 10AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.3m 6s period and expected on Friday (Aug 21) at 4AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 10PM (Thu 20th Aug) | 3.5ft (1.0m) 5s |
| Best Surf | 10PM (Thu 20th Aug) | 3.5ft (1.0m) 5s |
| Most Powerful | 10AM (Thu 20th Aug) | 5.5ft (1.7m) 6s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Alright, let's be real with you, it's looking pretty grim out there. For the next week and a half, you can just leave the boards in the car. There's a long stretch with absolutely no surf to get excited about. We're talking a solid 8 to 9 days of flatness, so don't be in a rush.
The first little window of hope shows up on the 24th of August. It's not much, but it's something. The Monday morning looks the pick with some glassy conditions and a little 4ft of SSW swell. The wind will be light, so it might be clean enough for a few waves. The afternoon sees the swell jump to 7ft, but the onshore wind will chop it up, so get out there early. It's definitely not going to win any awards, but it’s the best we've got.
After that, it's back to the waiting game. The next chance for anything is around the 30th of August. We have a bit more size, around 6ft, but it's short-period stuff and the wind will be howling. The surface will be clean enough, but the waves will be messy and lack any real push. This one is for the experienced crew who don't mind a challenge. The water temp is about normal for this time of year.
Bottom line, there is no standout day here, it's all pretty average. The morning of the 24th is the only real shot at a surfable wave, and even that is marginal. The 30th might have some power, but the quality won't be there. For the most part, it might be a better time to take up kite surfing because the paddle surfing looks like a write-off.
Rusty.
Short Range ForecastMostly dry. Very mild (max 16°C on Fri night, min 13°C on Fri night). Wind will be generally light. | Days 4-6 Weather SummaryHeavy rain (total 23mm), heaviest during Mon night. Very mild (max 18°C on Mon night, min 14°C on Tue night). Winds increasing (light winds from the WSW on Tue afternoon, fresh winds from the W by Wed night). | ||||||||||||||||||||
Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | |||||||||||||||
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) | W 8 | SW 6 | SW 6 | — | SW 2 | SW 3 | NW 3 | SW 5 | SSW 4 | SW 4 | SW 6 | SW 4 | W 4 | SW 5 | W 5 | WSW 6 | WSW 5 | SW 6 | SW 5 | SW 13 | SW 13 |
Wave Graph  | |||||||||||||||||||||
 kJ | 1 | 1 | 1 | 0 | 1 | 3 | 3 | 4 | 34 | 15 | 16 | 10 | 38 | 92 | 142 | 201 | 90 | 19 | 7 | 7 | 7 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | off | glassy | on | cross-on | cross | on | on | cross | cross-on | cross-on | cross-on | on | cross-on | cross-on | cross-on | cross-off | cross-off | cross | cross-off |
High Tide | 11:46AM4.02m | 00:00AM4.50m | 12:25PM3.91m | 00:40AM4.27m | 1:04PM3.73m | 1:21AM3.95m | 1:44PM3.51m | 2:05AM3.58m | 2:29PM3.25m | 2:56AM3.21m | 3:26PM3.00m | 4:05AM2.90m | 4:46PM2.83m | ||||||||
Low Tide | 6:15AM-0.35m | 6:25PM0.02m | 6:55AM-0.16m | 7:05PM0.20m | 7:34AM0.15m | 7:45PM0.46m | 8:13AM0.53m | 8:25PM0.77m | 8:54AM0.92m | 9:10PM1.10m | 9:40AM1.27m | 10:08PM1.38m | 10:45AM1.54m | 11:34PM1.55m | |||||||
 | |  | | |  | |  |  | | | | | |  |  | |  |  | | | |
 | 5:56 | — | — | 5:58 | — | — | 6:00 | — | — | 6:01 | — | — | 6:03 | — | — | 6:05 | — | — | 6:07 | — | — |
 | — | 8:45 | — | — | 8:44 | — | — | 8:42 | — | — | 8:39 | — | — | 8:37 | — | — | 8:36 | — | — | 8:32 | — |
mm | — | — | — | — | — | — | — | — | 10 | — | — | 9 | — | — | 1 | 2 | 1 | — | — | — | — |
Temp °C | 15 | 16 | 15 | 15 | 15 | 15 | 15 | 16 | 18 | 16 | 17 | 16 | 15 | 16 | 16 | 15 | 16 | 15 | 14 | 15 | 14 |
Feels °C | 11 | 13 | 13 | 14 | 12 | 12 | 14 | 13 | 18 | 13 | 15 | 14 | 11 | 12 | 11 | 9 | 11 | 12 | 10 | 11 | 11 |
Swell 1 Height (m) Direction Period (s) | SW 6 | SW 6 | N 4 | — | — | — | SW 4 | NW 3 | — | SW 4 | SW 6 | — | SW 16 | SW 15 | SW 16 | SW 15 | SW 14 | SW 6 | SW 5 | N 5 | SW 13 |
| kJ | 1 | 1 | 1 | — | — | — | 2 | 3 | — | 15 | 16 | — | 10 | 9 | 10 | 8 | 8 | 19 | 5 | 20 | 7 |
Swell 2 Height (m) Direction Period (s) | W 8 | — | SW 6 | — | — | — | — | SW 5 | — | SW 7 | NW 4 | — | — | — | — | — | — | SW 14 | SW 14 | SW 5 | SW 4 |
| kJ | 1 | — | 1 | — | — | — | — | 4 | — | 2 | 8 | — | — | — | — | — | — | 8 | 7 | 1 | 1 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | S 17 | — | — | — | — | — | — | — | SW 13 | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | 6 | — | — | — | — | — | — | — | 7 | — |
Wind waves Height (m) Direction Period (s) | N 4 | N 4 | — | — | SW 2 | SW 3 | NW 3 | — | SSW 4 | NW 3 | — | SW 4 | W 4 | SW 5 | W 5 | WSW 6 | WSW 5 | NNW 5 | NNW 6 | WNW 4 | N 5 |
| kJ | 13 | 8 | — | — | 1 | 3 | 3 | — | 34 | 5 | — | 10 | 38 | 92 | 142 | 201 | 90 | 66 | 55 | 2 | 27 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 333 | 442 | 261 | 256 | 285 | 212 | 258 | 264 | 393 | 329 | 381 | 221 | 261 | 521 | 261 | 244 | 506 | 172 | 53 | 258 | 211 |
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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