Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 4 Aug 2026:
- Most powerful swell: Thursday 6 Aug, 1AM (local time) - 7ft (2.1m), 6s period, WNW swell with 329 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 2.1m 6s and forecast to arrive on Thursday (Aug 06) at 1AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.9m 5s period and expected on Tuesday (Aug 11) at 1AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 1AM (Thu 6th Aug) | 7ft (2.1m) 6s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Alright, let’s see what’s cookin’ at Cable Bay (Porth Trecastell). I gotta be straight with you – this forecast is a bummer. We’ve got a big dry spell of garbage surf at the start, and it takes a while before anything looks even remotely rideable.
The first chance you’ll see anything with a pulse is Wednesday morning, August 5th. There’s a lumpy 6ft swell from the west, but it’s getting ripped apart by a fresh 19 mph cross-onshore wind. The wave energy is moderate at 207, but the wind is gonna turn it into a washing machine. Honestly, that’s more a kiteboarder’s day than a surfer’s.
Things clean up on Sunday, August 9th. The morning is glassy, with a tiny 2ft SW swell – the energy is weak at 20. It’s small, but the water’s a little warmer than usual for this time of year, sitting at 62°. The afternoon swings to a clean cross-offshore breeze, but the swell is fading fast.
The one that’s worth holding out for hits Monday, August 17th, in the afternoon. It’s not a big one, but we get a 4ft swell from the SW, with a onshore wind that’s only a light 9 mph. The wave energy is moderate at 51. The swell direction matches what the spot likes – straight out of the SW. The wind won’t be perfect, but it’s way better than the rest of the slop we’ve been seeing. This is an intermediate wave, fairly consistent, and crowds are possible, but with this run of tiny surf, it shouldn’t be too crazy.
Beyond that, it’s all tiny, weak dribble. So mark that Monday afternoon. Otherwise, you’re gonna be staring at flat water.
Rusty.
Short Range ForecastLight rain (total 5mm), mostly falling on Mon afternoon. Warm (max 20°C on Mon afternoon, min 13°C on Wed night). Winds increasing (calm on Mon afternoon, fresh winds from the W by Wed morning). | Days 5-7 Weather SummaryMostly dry. Very mild (max 17°C on Sat morning, min 14°C on Thu night). Wind will be generally light. | |||||||||||||||||||
Mon 3 | Tuesday 4 | Wednesday 5 | Thursday 6 | Friday 7 | Saturday 8 | Sunday 9 | ||||||||||||||
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 8 | SW 8 | SSW 5 | SSW 5 | SSW 6 | W 6 | WSW 5 | WNW 6 | NW 5 | SW 6 | SW 6 | SW 5 | S 12 | SW 5 | SSW 4 | SW 5 | SW 5 | SW 5 | SW 7 | SSW 6 |
Wave Graph  | ||||||||||||||||||||
 kJ | 11 | 10 | 67 | 59 | 96 | 207 | 94 | 329 | 89 | 12 | 8 | 4 | 3 | 31 | 10 | 94 | 65 | 14 | 7 | 4 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-off | cross-on | on | cross-on | cross-on | cross-on | cross-on | cross | on | cross-on | on | on | cross-on | on | on | cross-on | glassy | cross-off | off |
High Tide | 1:07AM3.94m | 1:32PM3.51m | 1:48AM3.77m | 2:18PM3.37m | 2:39AM3.55m | 3:15PM3.22m | 3:44AM3.33m | 4:28PM3.12m | 5:06AM3.20m | 5:53PM3.16m | 6:34AM3.25m | 7:10PM3.38m | ||||||||
Low Tide | 7:41PM0.62m | 8:12AM0.50m | 8:22PM0.79m | 8:55AM0.70m | 9:10PM0.99m | 9:47AM0.92m | 10:11PM1.16m | 10:55AM1.10m | 11:32PM1.22m | 12:19PM1.13m | 1:01AM1.07m | 1:38PM0.97m | 2:14AM0.73m | |||||||
 |  | |  |  |  | |  | | |  | | |  | | | |  | | | |
 | — | — | 5:37 | — | — | 5:39 | — | — | 5:41 | — | — | 5:43 | — | — | 5:45 | — | — | 5:47 | — | — |
 | — | 9:09 | — | — | 9:07 | — | — | 9:06 | — | — | 9:04 | — | — | 9:01 | — | — | 9:00 | — | 8:58 | — |
mm | 2 | 1 | 1 | — | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 20 | 17 | 19 | 18 | 17 | 15 | 17 | 16 | 14 | 15 | 15 | 15 | 16 | 16 | 17 | 17 | 17 | 17 | 19 | 17 |
Feels °C | 17 | 16 | 16 | 14 | 13 | 8 | 11 | 10 | 9 | 11 | 12 | 12 | 12 | 13 | 14 | 13 | 15 | 16 | 17 | 14 |
Swell 1 Height (m) Direction Period (s) | SW 8 | SW 8 | — | — | SSW 6 | — | S 13 | S 13 | SW 6 | N 5 | N 4 | WNW 3 | — | SW 5 | WNW 3 | — | SW 5 | SW 5 | SW 7 | SSW 6 |
| kJ | 11 | 10 | — | — | 96 | — | 3 | 3 | 30 | 19 | 1 | 2 | — | 26 | 1 | — | 65 | 14 | 7 | 4 |
Swell 2 Height (m) Direction Period (s) | NE 4 | SSW 4 | — | — | — | — | — | — | S 13 | SW 6 | SW 12 | SW 5 | S 12 | SW 12 | SW 11 | — | — | S 12 | WNW 3 | — |
| kJ | 1 | 1 | — | — | — | — | — | — | 3 | 12 | 6 | 4 | 3 | 5 | 5 | — | — | 3 | 2 | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | NW 5 | — | — | — | — | — | — | — | — | NNW 3 | — |
| kJ | — | — | — | — | — | — | — | — | — | 3 | — | — | — | — | — | — | — | — | 1 | — |
Wind waves Height (m) Direction Period (s) | S 4 | — | SSW 5 | SSW 5 | WNW 4 | W 6 | WSW 5 | WNW 6 | NW 5 | WNW 4 | SW 6 | — | SSW 3 | SW 5 | SSW 4 | SW 5 | — | NW 3 | — | NW 3 |
| kJ | 1 | — | 67 | 59 | 8 | 207 | 94 | 329 | 89 | 6 | 8 | — | 3 | 31 | 10 | 94 | — | 3 | — | 3 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 150 | 150 | 277 | 272 | 277 | 393 | 480 | 173 | 282 | 272 | 282 | 261 | 261 | 261 | 285 | 302 | 96 | 158 | 302 | 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.
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