Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 9 Sep 2026:
- Best quality surf: Tuesday 15 Sep, 10PM (local time) - 4.5ft (1.3m), 6s period, SSW swell with cross-offshore winds.
- Most powerful swell: Thursday 10 Sep, 4PM (local time) - 8ft (2.4m), 7s period, SSW swell with 530 kJ wave energy.
- Next surfable swell (1★+): Tuesday 15 Sep, 10PM (local time) - 4.5ft (1.3m), 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 Tuesday (Sep 15) at 10PM. The primary swell is predicted to be 1.3m and 6s period. 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 2.4m 7s and forecast to arrive on Thursday (Sep 10) at 4PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.4m 6s period and expected on Wednesday (Sep 09) at 10AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 10PM (Tue 15th Sep) | 4.5ft (1.3m) 6s |
| Best Surf | 10PM (Tue 15th Sep) | 4.5ft (1.3m) 6s |
| Most Powerful | 4PM (Thu 10th Sep) | 8ft (2.4m) 7s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Alright, Rusty here. Let's talk about what's on offer for the next couple of weeks.
Honestly, I'm looking at a pretty grim stretch ahead. The pattern is flat and messy for days on end. There's a lot of wind from the wrong directions, and the swell is just not cooperating. We're looking at a solid gap of about a week with no real surf to speak of.
From the start of the forecast period on Wednesday the 9th, right through to Tuesday the 15th, it's a write-off. We've got tiny 1ft to 2ft swells from the southwest, but the wind is all over the shop – cross-shore, onshore, and strong. The energy is weak, barely registering 15 to 19. It's poor, choppy, and lumpy. Not worth paddling out.
Things get a bit bigger on the 10th with a short-period 5ft to 8ft SSW swell, but that's accompanied by a fresh to strong breeze from the same direction, making it a total mess. The energy is there – hitting 154 and then 530 – but it's just not surfable. It's a kite-surfing kind of situation, not a paddle-surfing one.
The first real glimpse of something comes on Wednesday the 16th. The morning at Cable Bay (Porth Trecastell) is clean with a light cross-offshore breeze from the ESE. The swell is a modest 4ft from the SSW, with a period of 6 seconds and moderate energy reading 131. The water is about average for this time of year. It's surfable, but it's very ordinary. The wind switches to a cross-onshore in the afternoon, so that window is tight.
After that, it's back to small, poor conditions until the very end of the forecast. Sunday the 21st and Monday the 22nd have some tiny, clean waves, but the swell is only 0.3ft to 2ft. It's a long-period groundswell from the south, with periods hitting 14 seconds, but there's just no size to make it work. The end of the run on the 23rd and 24th shows a little more promise with a 4ft to 4ft NW swell and clean, offshore winds. The energy is still only moderate (56 to 74), but it's the best we've seen in a while. It's a promising but less certain call given how far out it is.
The one standout, if you can call it that, is the morning of Wednesday the 16th. It's the only window where the conditions aren't completely miserable, and the break is fairly consistent. Don't expect much, but it's the best on offer.
Rusty.
Short Range ForecastLight rain (total 5mm), mostly falling on Thu afternoon. Very mild (max 17°C on Thu night, min 13°C on Tue night). Winds decreasing (strong winds from the SSW on Thu morning, light winds from the WNW by Fri afternoon). | Days 4-6 Weather SummaryLight rain (total 6mm), mostly falling on Fri night. Very mild (max 18°C on Mon afternoon, min 13°C on Fri night). Winds decreasing (strong winds from the SSW on Sat morning, light winds from the WSW by Sun afternoon). | ||||||||||||||||||||
Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | Sunday 13 | Monday 14 | Tuesday 15 | |||||||||||||||
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 8 | SW 8 | SW 4 | SSW 6 | SSW 7 | SSW 7 | SW 7 | SSW 7 | SSW 4 | SW 7 | SW 7 | SW 7 | SSW 6 | SW 6 | SSW 3 | SSW 5 | SSW 5 | SSW 6 | SSW 5 | SSW 4 | SSW 6 |
Wave Graph  | |||||||||||||||||||||
 kJ | 15 | 14 | 24 | 154 | 530 | 134 | 47 | 30 | 24 | 381 | 271 | 46 | 16 | 9 | 8 | 62 | 36 | 97 | 48 | 18 | 148 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross | cross-on | cross-on | cross-on | cross-on | cross | cross | cross-on | on | on | cross | cross | on | cross-on | cross-on | on | cross-on | on | on | cross-off |
High Tide | 8:48AM3.63m | 8:58PM4.11m | 9:29AM3.86m | 9:39PM4.37m | 10:06AM4.03m | 10:17PM4.51m | 10:42AM4.11m | 10:54PM4.52m | 11:16AM4.11m | 11:30PM4.39m | 11:50AM4.02m | 00:07AM4.16m | 12:24PM3.85m | 00:44AM3.84m | |||||||
Low Tide | 3:19PM0.38m | 3:49AM-0.10m | 4:02PM0.12m | 4:31AM-0.30m | 4:43PM-0.03m | 5:10AM-0.34m | 5:22PM-0.06m | 5:48AM-0.24m | 5:59PM0.01m | 6:23AM-0.01m | 6:35PM0.19m | 6:58AM0.30m | 7:12PM0.44m | ||||||||
 | |  |  |  |  |  | | | |  |  | | |  | | | | | | | |
 | 6:39 | — | — | 6:41 | — | — | 6:43 | — | — | 6:45 | — | — | 6:47 | — | — | 6:48 | — | — | 6:50 | — | — |
 | — | 7:49 | — | — | 7:46 | — | — | 7:44 | — | — | 7:42 | — | — | 7:38 | — | — | 7:37 | — | — | 7:35 | — |
mm | — | — | — | 1 | 3 | 1 | — | — | 3 | 3 | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 14 | 14 | 15 | 16 | 16 | 17 | 14 | 14 | 16 | 16 | 17 | 15 | 13 | 14 | 15 | 16 | 18 | 17 | 18 | 18 | 19 |
Feels °C | 9 | 11 | 11 | 10 | 12 | 15 | 11 | 12 | 9 | 9 | 12 | 10 | 11 | 12 | 12 | 14 | 16 | 16 | 16 | 18 | 19 |
Swell 1 Height (m) Direction Period (s) | SW 8 | N 5 | N 4 | — | — | SSW 7 | SW 7 | SSW 7 | — | — | SW 7 | SW 7 | SSW 6 | NNW 5 | — | — | — | S 12 | — | — | W 11 |
| kJ | 15 | 27 | 1 | — | — | 134 | 47 | 30 | — | — | 271 | 46 | 16 | 7 | — | — | — | 3 | — | — | 2 |
Swell 2 Height (m) Direction Period (s) | — | SW 8 | — | — | — | — | — | NW 4 | — | — | — | — | W 3 | SW 6 | — | — | — | — | — | — | — |
| kJ | — | 14 | — | — | — | — | — | 5 | — | — | — | — | 2 | 9 | — | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | NNW 6 | WNW 4 | SW 4 | SSW 6 | SSW 7 | W 3 | WNW 4 | — | SSW 4 | SW 7 | — | NNW 5 | NNW 5 | WNW 3 | SSW 3 | SSW 5 | SSW 5 | SSW 6 | SSW 5 | SSW 4 | SSW 6 |
| kJ | 136 | 5 | 24 | 154 | 530 | 6 | 10 | — | 24 | 381 | — | 39 | 26 | 1 | 8 | 62 | 36 | 97 | 48 | 18 | 148 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 173 | 44 | 186 | 342 | 471 | 44 | 173 | 44 | 231 | 256 | 568 | 173 | 172 | 150 | 172 | 198 | 256 | 256 | 276 | 286 | 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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