Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 5 Aug 2026:
- Most powerful swell: Thursday 6 Aug, 4AM (local time) - 4.5ft (1.3m), 5s period, NW swell with 96 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 1.3m 5s and forecast to arrive on Thursday (Aug 06) at 4AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 5s period and expected on Thursday (Aug 06) at 10AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 4AM (Thu 6th Aug) | 4.5ft (1.3m) 5s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Alright mates, Rusty here with the lowdown. This 16-day forecast for Cable Bay is a real bummer. We’re staring down a long dry spell of poor surf, with hardly any swell and the wind often blowing the wrong way. For most of this, you’re best off finding something else to do.
The first half-decent window doesn’t appear till Monday, August 10th afternoon. That’s a solid five-day stretch with nothing to ride. That afternoon, we’ve got a tiny 1ft swell from the NW, with a clean cross-offshore breeze. The wave energy is a weak 8, so it’s not going to light anyone’s fire, but at least it’s clean. Don’t get your hopes up.
The biggest pulse of the whole run comes on Thursday, August 20th, with a 3ft swell from the SSW. The combined energy hits 57 – still weak, but it’s the best we’ll see. The problem is a strong cross-onshore wind, making it lumpy and choppy. By Thursday afternoon, the wind is a near gale from the south at 31 mph, with rain and totally blown-out conditions. That’s a washout.
The water is about 63°F, which is a touch warmer than usual for this time of year. That’s the only silver lining.
There’s no standout day here. The lack of any consistent quality means this is a pretty normal blank run for the area. I wouldn’t hold my breath.
Rusty.
Short Range ForecastLight rain (total 3mm), mostly falling on Wed afternoon. Very mild (max 17°C on Wed afternoon, min 13°C on Wed night). Winds decreasing (fresh winds from the WNW on Wed night, calm by Thu night). | Days 5-7 Weather SummaryMostly dry. Warm (max 22°C on Tue morning, min 16°C on Sat night). Wind will be generally light. | |||||||||||||||||||
Wed 5 | Thursday 6 | Friday 7 | Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | ||||||||||||||
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 5 | NW 5 | SW 6 | SW 6 | SW 4 | SW 4 | S 12 | SW 5 | SSW 4 | SSW 4 | SW 5 | SSW 4 | SW 6 | SW 6 | SW 6 | NW 3 | S 11 | S 11 | SW 6 | S 11 |
Wave Graph  | ||||||||||||||||||||
 kJ | 117 | 73 | 13 | 9 | 14 | 6 | 3 | 23 | 17 | 42 | 25 | 10 | 7 | 6 | 5 | 3 | 2 | 2 | 1 | 2 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross | cross | on | cross | on | on | cross-on | cross-on | cross-on | cross-on | cross-on | on | glassy | cross-on | cross-off | off | cross-on | cross-on | cross-on |
High Tide | 2:39AM3.55m | 3:15PM3.22m | 3:44AM3.33m | 4:28PM3.12m | 5:06AM3.20m | 5:53PM3.16m | 6:34AM3.25m | 7:10PM3.38m | 7:48AM3.43m | 8:14PM3.71m | 8:49AM3.66m | 9:07PM4.05m | ||||||||
Low Tide | 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 | 2:42PM0.68m | 3:13AM0.33m | 3:34PM0.38m | ||||||||
 |  |  |  |  | | |  | | | | | | | | | | | | | |
 | — | — | 5:41 | — | — | 5:43 | — | — | 5:45 | — | — | 5:47 | — | — | 5:48 | — | — | 5:50 | — | — |
 | — | 9:06 | — | — | 9:04 | — | — | 9:01 | — | — | 9:00 | — | 8:58 | — | — | 8:57 | — | — | 8:54 | — |
mm | 2 | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 17 | 15 | 14 | 15 | 16 | 16 | 16 | 15 | 17 | 18 | 17 | 18 | 19 | 19 | 19 | 21 | 18 | 22 | 22 | 19 |
Feels °C | 12 | 10 | 10 | 12 | 14 | 14 | 12 | 11 | 13 | 13 | 14 | 16 | 18 | 19 | 17 | 18 | 15 | 20 | 20 | 17 |
Swell 1 Height (m) Direction Period (s) | S 13 | SW 6 | SW 6 | N 5 | SW 4 | SW 4 | — | SW 12 | SW 11 | — | SW 7 | SW 7 | SW 4 | SW 6 | SW 6 | NW 3 | SW 6 | N 4 | NE 4 | — |
| kJ | 3 | 28 | 13 | 12 | 14 | 4 | — | 5 | 5 | — | 2 | 7 | 3 | 6 | 5 | 3 | 1 | 1 | 1 | — |
Swell 2 Height (m) Direction Period (s) | — | SW 13 | S 13 | WNW 4 | N 4 | WNW 3 | S 12 | — | — | SW 11 | S 11 | S 12 | SW 6 | SW 12 | — | SSW 6 | S 11 | SW 6 | — | SW 6 |
| kJ | — | 7 | 3 | 3 | 2 | 1 | 3 | — | — | 5 | 2 | 3 | 7 | 6 | — | 3 | 2 | 1 | — | 1 |
Swell 3 Height (m) Direction Period (s) | — | — | — | S 12 | SW 12 | SW 12 | S 6 | — | — | — | — | — | SW 12 | — | — | — | — | S 11 | SW 6 | S 11 |
| kJ | — | — | — | 3 | 6 | 6 | 1 | — | — | — | — | — | 6 | — | — | — | — | 2 | 1 | 2 |
Wind waves Height (m) Direction Period (s) | WSW 5 | NW 5 | NW 5 | SW 6 | — | SW 4 | SSW 4 | SW 5 | SSW 4 | SSW 4 | SW 5 | SSW 4 | — | — | NW 3 | NW 3 | N 4 | — | — | — |
| kJ | 117 | 73 | 60 | 9 | — | 6 | 3 | 23 | 17 | 42 | 25 | 10 | — | — | 3 | 2 | 5 | — | — | — |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 466 | 333 | 272 | 284 | 272 | 277 | 261 | 256 | 256 | 261 | 158 | 261 | 244 | 256 | 256 | 294 | 259 | 296 | 307 | 178 |
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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