Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 25 Aug 2026:
- Best quality surf: Sunday 30 Aug, 1AM (local time) - 3.5ft (1.0m), 8s period, SW swell with glassy winds.
- Most powerful swell: Tuesday 1 Sep, 4PM (local time) - 10ft (3.0m), 8s period, SSW swell with 1,051 kJ wave energy.
- Next surfable swell (1★+): Sunday 30 Aug, 1AM (local time) - 3.5ft (1.0m), 8s period with SW 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 Sunday (Aug 30) at 1AM. The primary swell is predicted to be 1.0m and 8s period with a secondary swell of 0.8m and 4s. 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 3.0m 8s and forecast to arrive on Tuesday (Sep 01) at 4PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.3m 4s period and expected on Saturday (Aug 29) at 1PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 1AM (Sun 30th Aug) | 3.5ft (1.0m) 8s |
| Best Surf | 1AM (Sun 30th Aug) | 3.5ft (1.0m) 8s |
| Most Powerful | 4PM (Tue 1st Sep) | 10ft (3.0m) 8s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Alright, let’s talk about what’s on the cards for Cable Bay (Porth Trecastrell). The water’s at 64°, which is a touch warmer than average for this time of year, so that’s a nice little bonus.
To be straight with you, the next week and a half is a total bust. The first solid recommendation is a long way off, and there’s a big gap of nothing until then. For the first week, it’s all tiny, messy, and blown out. Tuesday the 25th has waves barely 0.3ft, with a decent cross-off wind in the morning, but there’s nothing to ride. It’s the same story through Wednesday, Thursday, and into the weekend – tiny swells, poor conditions, and onshore or cross-onshore winds spoiling any chance of a wave. The swell energy is weak, with values barely cracking 10 in the early days.
The only real standout, and it’s a long-range promise, lands on Tuesday the 1st of September. We’ve got a big pulse of swell coming in at 10ft from the SSW, with a period of 7-8 seconds. The combined energy is massive at 742 to 1051, so there’s serious power behind it. But – and it’s a big but – the wind is forecast to be a near gale from the SSW, straight onshore. That’s going to turn it into a washing machine. This is expert-only territory with that size and wind, and honestly, it looks more interesting for kite surfing than paddle surfing. The rest of the first week of September is a mix of messy, lumpy, and cross-onshore conditions, with no real clean windows.
Don’t get your hopes up for the rest of the outlook either. The second week continues with strong winds and cross-onshore chop, with most days seeing fresh to strong breezes. There’s nothing that shapes up as a clean, rideable wave for a surfer. It’s a long, dry run.
Rusty
Short Range ForecastModerate rain (total 11mm), heaviest on Thu morning. Warm (max 21°C on Wed afternoon, min 16°C on Wed morning). Winds decreasing (fresh winds from the E on Tue night, light winds from the S by Thu afternoon). | Days 4-6 Weather SummaryHeavy rain (total 26mm), heaviest during Sun morning. Very mild (max 17°C on Fri morning, min 13°C on Sun night). Winds increasing (calm on Sat night, strong winds from the W by Sun night). | ||||||||||||||||||||
Tuesday 25 | Wednesday 26 | Thursday 27 | Friday 28 | Saturday 29 | Sunday 30 | Monday 31 | |||||||||||||||
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 13 | SW 13 | SSW 8 | SW 8 | SSW 8 | SSW 7 | SSW 7 | SW 7 | SSW 4 | SSW 8 | SSW 7 | SSW 7 | SSW 6 | SSW 8 | SW 8 | SW 8 | SSW 8 | SSW 7 | SSW 7 | WSW 4 | SW 5 |
Wave Graph  | |||||||||||||||||||||
 kJ | 7 | 7 | 7 | 17 | 12 | 5 | 6 | 2 | 17 | 202 | 86 | 30 | 55 | 158 | 142 | 72 | 51 | 40 | 34 | 30 | 49 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | off | cross-off | cross-off | cross-off | off | cross-off | cross-on | cross-on | on | on | cross-on | on | cross-on | glassy | cross-on | on | cross-on | cross-on | cross-on | on |
High Tide | 9:03PM3.55m | 9:25AM3.40m | 9:35PM3.81m | 9:55AM3.58m | 10:04PM4.02m | 10:23AM3.73m | 10:32PM4.18m | 10:51AM3.84m | 11:00PM4.28m | 11:19AM3.92m | 11:30PM4.30m | 11:49AM3.93m | 00:03AM4.23m | ||||||||
Low Tide | 3:12PM0.93m | 3:39AM0.68m | 3:47PM0.67m | 4:13AM0.41m | 4:20PM0.46m | 4:45AM0.20m | 4:53PM0.30m | 5:18AM0.06m | 5:26PM0.21m | 5:52AM0.00m | 6:01PM0.20m | 6:27AM0.05m | 6:37PM0.27m | ||||||||
 | |  |  |  |  |  |  |  | | | | |  | | | | | | |  | |
 | 6:13 | — | — | 6:16 | — | — | 6:16 | — | — | 6:18 | — | — | 6:20 | — | — | 6:22 | — | — | 6:24 | — | — |
 | — | 8:23 | — | — | 8:22 | — | — | 8:20 | — | — | 8:16 | — | — | 8:15 | — | — | 8:13 | — | — | 8:09 | — |
mm | — | — | — | — | 2 | 1 | 6 | 2 | — | — | — | 4 | 2 | — | — | 10 | 4 | 6 | — | — | — |
Temp °C | 20 | 20 | 20 | 20 | 21 | 21 | 17 | 17 | 16 | 17 | 17 | 17 | 16 | 17 | 17 | 17 | 16 | 15 | 15 | 18 | 17 |
Feels °C | 18 | 18 | 14 | 20 | 21 | 21 | 17 | 18 | 14 | 14 | 16 | 15 | 14 | 14 | 16 | 12 | 10 | 9 | 8 | 14 | 13 |
Swell 1 Height (m) Direction Period (s) | SW 13 | — | SSW 8 | NE 5 | SSW 8 | SSW 7 | NE 4 | NNE 4 | — | — | SSW 7 | SSW 7 | SSW 6 | SSW 8 | SW 8 | SW 8 | SSW 8 | SSW 7 | SSW 7 | NW 4 | — |
| kJ | 7 | — | 7 | 4 | 12 | 5 | 3 | 2 | — | — | 86 | 30 | 55 | 158 | 142 | 72 | 51 | 40 | 34 | 6 | — |
Swell 2 Height (m) Direction Period (s) | SW 8 | SW 13 | S 13 | SW 8 | NE 5 | S 12 | SSW 7 | SW 7 | — | — | — | S 11 | NNW 5 | — | — | NW 4 | WNW 3 | — | SW 10 | SSW 10 | — |
| kJ | 3 | 7 | 3 | 17 | 3 | 3 | 5 | 2 | — | — | — | 2 | 2 | — | — | 8 | 1 | — | 4 | 10 | — |
Swell 3 Height (m) Direction Period (s) | — | SW 8 | S 13 | SSE 4 | — | — | SW 12 | — | — | — | — | — | — | — | — | — | N 4 | — | — | — | — |
| kJ | — | 3 | 3 | 2 | — | — | 6 | — | — | — | — | — | — | — | — | — | 1 | — | — | — | — |
Wind waves Height (m) Direction Period (s) | E 3 | NE 5 | ENE 4 | — | — | — | — | — | SSW 4 | SSW 8 | WNW 3 | WNW 3 | — | NW 5 | WNW 4 | SW 5 | — | NNE 3 | WNW 4 | WSW 4 | SW 5 |
| kJ | 4 | 6 | 19 | — | — | — | — | — | 17 | 202 | 4 | 4 | — | 63 | 19 | 15 | — | 1 | 15 | 30 | 49 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 261 | 258 | 181 | 322 | 300 | 285 | 258 | 258 | 179 | 106 | 283 | 277 | 168 | 44 | 0 | 256 | 261 | 574 | 549 | 506 | 277 |
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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