Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 30 Aug 2026:
- Most powerful swell: Friday 4 Sep, 7AM (local time) - 8ft (2.5m), 7s period, WSW swell with 672 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 2.5m 7s and forecast to arrive on Friday (Sep 04) at 7AM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.1m 5s period and expected on Saturday (Sep 05) at 10AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 7AM (Fri 4th Sep) | 8ft (2.5m) 7s |
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 what Cable Bay (Porth Trecastrell) has in store for us. I gotta be straight with you, the outlook for the next 16 days is a tough one. We're looking at a long stretch of nothing good, and the conditions are just not playing ball.
We kick off Sunday the 30th of August with a messy combo. The water is sitting at a very unusual 64°, which is way warmer than normal for this time of year. But that's where the good news stops. The swell is small and weak, with the combined energy only around 113 (weak), coming from the SSW at under 3 feet. On top of that, the wind is a cross-onshore breeze at 16 mph, making for a choppy, poor surf. This continues through the afternoon, with the wind picking up, and the period dropping to a short and weak 5 seconds. Honestly, it's a write-off.
Monday the 31st is a bit bigger with a 6 ft swell (combined energy 238 - moderate), but the wind is a messy cross-shore, not doing us any favours. The period is still a short 6 seconds, so it's lumpy and unappealing. The trend of poor surf and onshore winds continues right into the first week of September. The swell gets a bit more size, like Wednesday the 2nd with 6 ft at 7 seconds (energy 305 - moderate), but it's all onshore wind at 22 mph. Not a single break in the clouds here.
There's a bit of a lull around the 5th and 6th with tiny, weak swells. By Friday the 4th of September, we see a bigger 8 ft swell from the WSW with a period of 7 seconds and a strong 25 mph cross-onshore wind, producing a combined energy of 580 (moderate). That's big enough for experts only, but the wind makes it a total mess. It's more of a kite-surfing setup than a paddle-surfing one.
The pattern holds through the weekend and into the next week. Even on the 10th of September, when we finally get a glassy morning, the swell is non-existent at 1 ft with a period of just 3 seconds (energy 3). It’s flat. We don't get any real improvement until the tail end of the outlook. Around Friday the 11th and Saturday the 12th of September, we get a small, clean bump. The swell is tiny (1 ft to 3 ft) but the wind turns offshore or glassy, with a period that stretches a bit to 7 seconds. The combined energy is still in the weak range (22 to 39).
For this entire 16-day window, it’s been a brutal stretch. There is no standout day. The best you can hope for is a clean but tiny wave on Saturday the 12th of September, with a 3 ft SE swell and a gentle offshore wind. It's not a recommendation, it's just the least bad option. Everything else is blown out, flat, or both. For an exposed spot like this, it's a real bummer.
Rusty.
Short Range ForecastLight rain (total 9mm), mostly falling on Sun morning. Very mild (max 18°C on Tue night, min 14°C on Sun night). Winds increasing (light winds from the W on Sun night, strong winds from the SSW by Tue night). | Days 4-6 Weather SummaryModerate rain (total 12mm), heaviest on Thu afternoon. Very mild (max 17°C on Wed morning, min 14°C on Thu night). Mainly strong winds. | ||||||||||||||||||||
Sunday 30 | Monday 31 | Tuesday 1 | Wednesday 2 | Thursday 3 | Friday 4 | Saturday 5 | |||||||||||||||
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) | SSW 8 | SSW 5 | SW 7 | WNW 6 | NW 5 | SSW 7 | SW 4 | SSW 5 | SW 6 | SW 7 | SSW 6 | SW 7 | SW 6 | SSW 6 | WSW 6 | WSW 7 | WSW 6 | NW 6 | SW 5 | SW 6 | SSW 5 |
Wave Graph  | |||||||||||||||||||||
 kJ | 113 | 103 | 116 | 176 | 57 | 21 | 41 | 90 | 114 | 305 | 209 | 263 | 119 | 176 | 340 | 580 | 238 | 133 | 17 | 9 | 68 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | cross | cross-on | on | on | on | on | on | on | on | on | on | on | cross-on | cross-on | cross | cross | on | cross-on |
High Tide | 11:19AM3.92m | 11:30PM4.30m | 11:49AM3.93m | 00:03AM4.23m | 12:23PM3.87m | 00:40AM4.07m | 1:01PM3.73m | 1:22AM3.82m | 1:47PM3.51m | 2:14AM3.50m | 2:44PM3.26m | 3:24AM3.18m | 4:06PM3.08m | ||||||||
Low Tide | 6:01PM0.20m | 6:27AM0.05m | 6:37PM0.27m | 7:03AM0.19m | 7:16PM0.42m | 7:43AM0.43m | 7:59PM0.63m | 8:28AM0.72m | 8:50PM0.88m | 9:25AM1.02m | 9:57PM1.11m | 10:40AM1.25m | 11:26PM1.19m | ||||||||
 |  |  |  | |  |  |  |  | |  |  | | | | | | | | | | |
 | 6:22 | — | — | 6:24 | — | — | 6:26 | — | — | 6:28 | — | — | 6:30 | — | — | 6:31 | — | — | 6:33 | — | — |
 | — | 8:13 | — | — | 8:09 | — | — | 8:07 | — | — | 8:06 | — | — | 8:02 | — | — | 8:00 | — | — | 7:59 | — |
mm | 2 | 2 | 1 | — | — | — | — | 1 | 3 | 1 | — | — | — | 5 | 5 | — | 1 | — | — | — | — |
Temp °C | 17 | 17 | 15 | 15 | 16 | 16 | 16 | 16 | 18 | 17 | 17 | 17 | 16 | 16 | 15 | 16 | 17 | 15 | 14 | 14 | 14 |
Feels °C | 14 | 12 | 12 | 9 | 12 | 13 | 12 | 11 | 15 | 12 | 12 | 13 | 12 | 11 | 10 | 9 | 11 | 9 | 11 | 12 | 10 |
Swell 1 Height (m) Direction Period (s) | — | — | SW 7 | SW 8 | SW 8 | SSW 7 | — | — | — | — | — | SW 15 | SW 14 | — | — | — | SW 14 | SW 6 | SW 5 | N 5 | — |
| kJ | — | — | 116 | 62 | 51 | 21 | — | — | — | — | — | 9 | 8 | — | — | — | 8 | 35 | 17 | 12 | — |
Swell 2 Height (m) Direction Period (s) | — | — | — | — | — | NNW 4 | — | — | — | — | — | — | — | — | — | — | — | SW 14 | SW 14 | WNW 4 | SW 13 |
| kJ | — | — | — | — | — | 4 | — | — | — | — | — | — | — | — | — | — | — | 8 | 7 | 5 | 7 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | SW 13 | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 7 | — |
Wind waves Height (m) Direction Period (s) | SSW 8 | SSW 5 | — | WNW 6 | NW 5 | W 3 | SW 4 | SSW 5 | SW 6 | SW 7 | SSW 6 | SW 7 | SW 6 | SSW 6 | WSW 6 | WSW 7 | WSW 6 | NW 6 | NW 5 | SW 6 | SSW 5 |
| kJ | 113 | 103 | — | 176 | 57 | 5 | 41 | 90 | 114 | 305 | 209 | 263 | 119 | 176 | 340 | 580 | 238 | 133 | 62 | 9 | 68 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 296 | 285 | 44 | 283 | 44 | 44 | 299 | 261 | 256 | 264 | 587 | 283 | 261 | 299 | 307 | 541 | 541 | 282 | 185 | 244 | 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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