Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 19 Aug 2026:
- Most powerful swell: Wednesday 19 Aug, 10PM (local time) - 3.5ft (1.0m), 5s period, SW swell with 50 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 1.0m 5s and forecast to arrive on Wednesday (Aug 19) at 10PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.2m 5s period and expected on Thursday (Aug 20) at 1PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 10PM (Wed 19th Aug) | 3.5ft (1.0m) 5s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Gather 'round, folks. Rusty here. I've been staring at the charts for Cable Bay (Porth Trecastell) and, well, it's a tough one. The next 16 days are looking pretty flat and disappointing for us. There's just nothing on the horizon that's going to get the stoke up. The water is sitting at 65°, which is much warmer than normal for this time of year, but that's about the only interesting thing going on.
The pattern is a long, drawn-out lull. From now through to the end of the month, the swell is tiny, with heights barely scraping 3 ft at best, and those are from short-period, weak windswells that are mostly blown out by onshore winds. The combined energy is pitiful, sitting at 45 on the best of the first few days. You'll see a lot of "poor surf conditions" tagged on the forecast, and that's the truth. The real kicker is that from the 21st of August through to the 2nd of September, the swell almost completely vanishes, with heights dropping to 0.3 ft and energy readings in the single digits. That's a massive gap of about 12 days where you'd be better off taking up golf.
The only time the swell even tries to flicker back to life is right at the very end of the window. On Monday, the 31st of August, we see a slight bump from the NW, with a height of 4 ft and energy climbing to 92. It's not much, but it's the best we've got. The wind is a cross-shore, which is okay, but it'll be a lumpy, confused mess. Then, on the 2nd of September, there's a bit of a NW swell again, hitting 4 ft in the morning, and the energy nudges up to 99. The wind is light and onshore, which is a problem. Given the small size, short period, and onshore wind, this setup honestly looks more interesting for kite surfing than paddle surfing.
So, realistically, there is no standout here. If you're desperate, the morning of the 31st of August might offer a few grovelly, cross-shore waves, but it's a long way out and the forecast confidence is low. Don't hold your breath.
Rusty.
Short Range ForecastModerate rain (total 12mm), heaviest on Wed night. Very mild (max 16°C on Wed morning, min 12°C on Thu night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 20°C on Mon afternoon, min 13°C on Sat morning). Wind will be generally light. | ||||||||||||||||||||
Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | |||||||||||||||
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) | WSW 4 | SW 4 | SW 5 | 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 14 | SW 13 | SW 13 | SW 13 | SW 13 |
Wave Graph  | |||||||||||||||||||||
 kJ | 25 | 23 | 41 | 12 | 11 | 8 | 7 | 7 | 7 | 8 | 8 | 8 | 8 | 7 | 8 | 8 | 7 | 7 | 7 | 7 | 6 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | cross-on | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | off | glassy | cross-off | cross-off | off | off | off |
High Tide | 2:29PM3.25m | 2:56AM3.21m | 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 | ||||||||
Low Tide | 9:10PM1.10m | 9:40AM1.27m | 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 | ||||||||
 | |  | |  |  |  | |  |  | | | | | | | | |  | | | |
 | 6:03 | — | — | 6:05 | — | — | 6:07 | — | — | 6:09 | — | — | 6:11 | — | — | 6:11 | — | — | 6:13 | — | — |
 | — | 8:37 | — | — | 8:36 | — | — | 8:32 | — | — | 8:30 | — | — | 8:29 | — | — | 8:27 | — | — | 8:23 | — |
mm | 1 | 1 | 6 | 3 | — | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 2 |
Temp °C | 16 | 16 | 16 | 15 | 15 | 14 | 14 | 16 | 14 | 14 | 15 | 14 | 15 | 16 | 15 | 18 | 20 | 19 | 18 | 18 | 16 |
Feels °C | 13 | 11 | 14 | 11 | 10 | 10 | 10 | 12 | 11 | 10 | 11 | 12 | 12 | 13 | 13 | 16 | 17 | 15 | 12 | 13 | 13 |
Swell 1 Height (m) Direction Period (s) | SW 16 | NW 4 | SW 5 | SW 6 | SW 6 | SSW 6 | SW 6 | W 4 | SW 13 | SW 15 | SW 15 | SW 15 | N 4 | N 4 | SW 14 | SW 14 | SW 14 | SW 13 | SSE 4 | — | SW 13 |
| kJ | 10 | 2 | 41 | 12 | 11 | 3 | 1 | 2 | 7 | 8 | 8 | 8 | 10 | 3 | 8 | 8 | 7 | 7 | 3 | — | 6 |
Swell 2 Height (m) Direction Period (s) | SW 16 | S 15 | SW 16 | SW 15 | SW 14 | SW 14 | SW 14 | SW 6 | — | — | — | S 12 | SW 14 | SW 14 | — | — | — | SW 13 | NE 4 | — | — |
| kJ | 10 | 5 | 10 | 8 | 8 | 8 | 7 | 1 | — | — | — | 3 | 8 | 7 | — | — | — | 7 | 1 | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | SW 13 | — | — | — | — | — | — | — | — | — | — | SW 13 | SW 13 | — |
| kJ | — | — | — | — | — | — | — | 7 | — | — | — | — | — | — | — | — | — | — | 7 | 7 | — |
Wind waves Height (m) Direction Period (s) | WSW 4 | SW 4 | WNW 4 | NNW 4 | N 5 | NNW 5 | NNW 5 | NNW 4 | NNW 5 | NNW 5 | NNW 4 | N 5 | — | NNW 4 | — | — | — | ENE 2 | — | — | — |
| kJ | 25 | 23 | 13 | 37 | 62 | 72 | 39 | 11 | 43 | 17 | 15 | 16 | — | 3 | — | — | — | 1 | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 256 | 244 | 297 | 173 | 830 | 185 | 185 | 284 | 272 | 233 | 211 | 211 | 272 | 302 | 211 | 256 | 258 | 256 | 261 | 211 | 172 |
Best forecast wave conditions in Anglesy | |||||||||||||||||||||
Best forecast wave conditions in United Kingdom | |||||||||||||||||||||
Header Global | |||||||||||||||||||||
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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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