Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 6 Aug 2026:
- Most powerful swell: Wednesday 12 Aug, 10PM (local time) - 3.5ft (1.0m), 5s period, SW swell with 43 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 12) 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 0.4m 5s period and expected on Thursday (Aug 06) at 7PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 10PM (Wed 12th Aug) | 3.5ft (1.0m) 5s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a look at the outlook for Cable Bay.
We’ve got a pretty grim picture for the next two weeks. The truth is, the first surf recommendation is a long time coming, and there’s a big gap with absolutely nothing worth paddling out for. The first chance for a wave doesn’t show up until Thursday, August 16th, and even then it’s a real struggle. Before that, we’re looking at a solid 10-day stretch of flat, weak, or messy conditions.
The water temperature is a touch warmer than normal for this time of year, at 62.9°F. That’s a nice bit of comfort, but it won’t help the lack of swell.
The first real standout, if you can call it that, is on Sunday, August 16th, in the afternoon. We’re looking at a clean, cross-off wind from the NNW at 12 mph, which is a major positive for the surface. The swell is a tiny 2.3 ft from the SSW, with a period of 6 seconds. The combined energy is still weak, only 55. It’s a very small, short-period wind swell, so it’s more about the clean surface than any real power. It’s a rare moment of clean conditions, but the waves are for the small-wave crew only.
For the rest of the period, the wind is mostly onshore or cross-onshore, and the swell is consistently under 1.6 ft. The wave energy is often in the single digits or low teens, which is basically flat. There’s a day on August 19th with a long period swell (16 seconds) from the south, but it’s only 0.3 ft. That’s just a big, slow-moving bump with no punch. The wind is also a strong breeze onshore that morning, making it messy.
Honestly, unless you’re desperate for a clean, glassy paddle on a very small day, there’s nothing to get excited about. The best bet is that Sunday afternoon, August 16th, for a few clean but tiny waves. The crowd is listed as “sometimes” at Cable Bay, so you might have company, but for this kind of swell, it’s unlikely to be busy.
Short Range ForecastMostly dry. Very mild (max 17°C on Fri afternoon, min 13°C on Thu morning). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 22°C on Tue afternoon, min 16°C on Sun night). Wind will be generally light. | ||||||||||||||||||||
Thursday 6 | Friday 7 | Saturday 8 | Sunday 9 | Monday 10 | Tuesday 11 | Wednesday 12 | |||||||||||||||
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) | NW 5 | SW 6 | SSW 4 | SW 4 | SW 5 | SSW 4 | SSW 4 | SSW 4 | SSW 4 | SW 4 | SW 6 | SSW 6 | SSW 6 | SSW 6 | SW 6 | SW 6 | SSW 3 | SSW 3 | SSW 4 | SSW 4 | SW 5 |
Wave Graph  | |||||||||||||||||||||
 kJ | 66 | 5 | 16 | 6 | 5 | 12 | 15 | 10 | 9 | 7 | 7 | 4 | 4 | 4 | 1 | 1 | 2 | 6 | 11 | 14 | 42 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | cross-on | on | on | cross-on | cross-on | on | cross-on | cross-on | on | glassy | cross | cross | off | on | on | cross-on | cross-on | cross-on | on |
High Tide | 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 | 9:40AM3.86m | 9:54PM4.35m | ||||||||
Low Tide | 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 | 4:04AM-0.04m | 4:20PM0.13m | |||||||||
 | |  | | |  | |  | | | | | | | |  | | | | | | |
 | 5:41 | — | — | 5:43 | — | — | 5:45 | — | — | 5:47 | — | — | 5:48 | — | — | 5:50 | — | — | 5:52 | — | — |
 | — | — | 9:04 | — | — | 9:01 | — | — | 9:00 | — | 8:58 | — | — | 8:57 | — | — | 8:54 | — | — | 8:52 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 14 | 15 | 16 | 16 | 17 | 15 | 17 | 17 | 16 | 17 | 19 | 18 | 18 | 20 | 18 | 21 | 22 | 19 | 20 | 20 | 18 |
Feels °C | 10 | 12 | 13 | 14 | 13 | 12 | 13 | 13 | 13 | 14 | 19 | 19 | 17 | 19 | 17 | 19 | 19 | 17 | 16 | 17 | 16 |
Swell 1 Height (m) Direction Period (s) | SW 6 | NNW 5 | SSW 4 | SW 4 | WNW 3 | SW 12 | SW 11 | S 11 | S 11 | SW 6 | SW 3 | SSW 6 | SSW 6 | SSW 6 | SW 6 | SW 6 | SW 6 | S 11 | SW 12 | SW 10 | SW 5 |
| kJ | 9 | 13 | 12 | 5 | 1 | 5 | 5 | 2 | 2 | 2 | 2 | 4 | 4 | 4 | 1 | 1 | 1 | 2 | 6 | 4 | 42 |
Swell 2 Height (m) Direction Period (s) | S 13 | SW 6 | N 4 | NW 3 | S 12 | — | — | — | S 11 | S 12 | SW 6 | S 12 | — | — | — | — | — | SW 11 | W 10 | SW 12 | SW 8 |
| kJ | 3 | 5 | 2 | 3 | 3 | — | — | — | 2 | 3 | 7 | 3 | — | — | — | — | — | 5 | 2 | 6 | 3 |
Swell 3 Height (m) Direction Period (s) | — | NW 4 | SW 12 | SW 12 | S 6 | — | — | — | — | — | SW 12 | — | — | — | — | — | — | — | SW 6 | — | — |
| kJ | — | 1 | 6 | 6 | 1 | — | — | — | — | — | 6 | — | — | — | — | — | — | — | 1 | — | — |
Wind waves Height (m) Direction Period (s) | NW 5 | WSW 4 | SW 4 | — | SW 5 | SSW 4 | SSW 4 | SSW 4 | SSW 4 | SW 4 | — | — | WNW 2 | — | — | — | SSW 3 | SSW 3 | SSW 4 | SSW 4 | — |
| kJ | 66 | 4 | 16 | — | 5 | 12 | 15 | 10 | 9 | 7 | — | — | 1 | — | — | — | 2 | 6 | 11 | 14 | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 282 | 284 | 272 | 277 | 261 | 256 | 256 | 256 | 256 | 260 | 256 | 261 | 256 | 258 | 259 | 296 | 298 | 233 | 277 | 272 | 96 |
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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