Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 5 Sep 2026:
- Most powerful swell: Tuesday 8 Sep, 10AM (local time) - 7ft (2.1m), 6s period, WSW swell with 333 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 2.1m 6s and forecast to arrive on Tuesday (Sep 08) at 10AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.7m 5s period and expected on Wednesday (Sep 09) at 4PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 10AM (Tue 8th Sep) | 7ft (2.1m) 6s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Alright, Rusty here. Let’s get into what’s lookin’ good for Cable Bay over the next couple of weeks.
Straight up, I’ve gotta be honest with you, this is a tough stretch for surf at Cable Bay (Porth Trecastell). We’ve got a long, painful gap right at the start. From now, right through Saturday the 7th of September, it’s all poor conditions with onshore or cross-onshore winds and messy, lumpy surf. The swell does build – we get a pulse on Tuesday the 8th with a 7 ft swell from the WSW, but that comes with a strong 25 mph cross-onshore wind, leaving the place blown out and messy. The combined energy is strong, hitting 333, but it’s just not rideable for a paddle. Honestly, for the first week, this setup looks more interesting for the kite-surfing crew than for us.
We finally get a little window of hope on Saturday the 12th of September, but the swell is tiny – just 1 ft from the SW. The saving grace is the wind goes glassy in the morning, so it’s clean. The combined energy is only 17, so it’s weak. You’d be on a log if you’re gonna surf anything. The water temp is about average for this time of year, so no surprises there.
Sunday the 13th sees a clean offshore wind from the ENE, but the swell drops to nearly nothing at 0.3 ft. It’s a flat spell with clean conditions. We get a few more scattered days of small, weak swell after that, but it never really puts anything together. We see a little pulse on Tuesday the 15th with a 3 ft swell from the W, but the wind goes cross-onshore again and it’s choppy.
By Friday the 18th, it’s a write-off with 34 mph winds and a total blowout. Then on Saturday the 19th, the wind finally goes offshore and glassy, but there is no swell at all to speak of – just flat, clean water. The very last day of the run, Sunday the 20th, we get a small 2 ft southerly-southwest swell with a clean offshore breeze, but it’s barely enough to break.
So the long and short of it is: there’s no real standout in this 16-day window. The best bet for a clean paddle would be that glassy morning on the 12th, but you’ll need a lot of board and a lot of patience for the tiny waves. It’s been a poor run, but for this area, these blank spells are more normal than not. Forecasts can change, but right now, I’d leave the boards in the van.
Rusty
Short Range ForecastLight rain (total 5mm), mostly falling on Mon afternoon. Very mild (max 19°C on Sun morning, min 14°C on Fri night). Winds increasing (light winds from the WSW on Sat morning, strong winds from the SW by Mon afternoon). | Days 4-6 Weather SummaryLight rain (total 4mm), mostly falling on Tue afternoon. Very mild (max 18°C on Thu afternoon, min 13°C on Mon night). Winds decreasing (strong winds from the WSW on Tue morning, light winds from the WSW by Wed night). | ||||||||||||||||||||
Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | |||||||||||||||
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) | W 5 | SW 6 | SSW 4 | SSW 5 | SSW 6 | SW 6 | SW 14 | SW 6 | SW 6 | WSW 6 | WSW 6 | W 6 | NW 6 | WSW 4 | SW 4 | SW 6 | SW 6 | WSW 4 | WNW 5 | WNW 5 | WNW 5 |
Wave Graph  | |||||||||||||||||||||
 kJ | 48 | 26 | 37 | 85 | 122 | 142 | 52 | 141 | 216 | 333 | 249 | 152 | 96 | 16 | 19 | 162 | 94 | 25 | 69 | 64 | 87 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | cross-on | cross-on | cross-on | cross-on | on | on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | on | cross-on | on | cross-on | cross | cross-on | cross-on |
High Tide | 4:06PM3.08m | 5:04AM3.02m | 5:48PM3.13m | 6:46AM3.12m | 7:12PM3.41m | 7:58AM3.37m | 8:11PM3.77m | 8:48AM3.63m | 8:58PM4.11m | 9:29AM3.86m | 9:39PM4.37m | 10:06AM4.03m | 10:17PM4.51m | ||||||||
Low Tide | 10:40AM1.25m | 11:26PM1.19m | 12:11PM1.26m | 00:57AM0.99m | 1:29PM1.03m | 2:07AM0.62m | 2:30PM0.70m | 3:02AM0.22m | 3:19PM0.38m | 3:49AM-0.10m | 4:02PM0.12m | 4:31AM-0.30m | 4:43PM-0.03m | ||||||||
 |  |  |  | |  | |  |  | |  |  | | | | | | | | | | |
 | 6:33 | — | — | 6:35 | — | — | 6:35 | — | — | 6:37 | — | — | 6:39 | — | — | 6:41 | — | — | 6:43 | — | — |
 | — | 7:59 | — | — | 7:55 | — | — | 7:53 | — | — | 7:52 | — | — | 7:49 | — | — | 7:46 | — | — | 7:44 | — |
mm | — | — | 1 | — | — | 1 | — | 3 | — | — | 1 | — | — | — | 3 | — | — | — | — | — | — |
Temp °C | 14 | 15 | 15 | 19 | 19 | 17 | 15 | 16 | 15 | 15 | 15 | 14 | 15 | 15 | 16 | 17 | 18 | 17 | 15 | 16 | 15 |
Feels °C | 11 | 11 | 11 | 12 | 13 | 14 | 9 | 9 | 9 | 7 | 8 | 7 | 8 | 11 | 13 | 13 | 13 | 13 | 8 | 11 | 10 |
Swell 1 Height (m) Direction Period (s) | SW 7 | WNW 4 | SW 13 | SW 13 | SW 13 | SW 12 | SW 14 | SW 13 | — | — | — | — | SW 6 | NNW 5 | NW 4 | — | — | SW 7 | SW 6 | SSW 6 | SW 6 |
| kJ | 7 | 3 | 7 | 7 | 6 | 6 | 51 | 27 | — | — | — | — | 20 | 24 | 4 | — | — | 22 | 10 | 22 | 16 |
Swell 2 Height (m) Direction Period (s) | SW 14 | NNW 5 | — | — | — | — | — | — | — | — | — | — | — | — | N 5 | — | — | — | — | — | — |
| kJ | 7 | 2 | — | — | — | — | — | — | — | — | — | — | — | — | 2 | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | SW 14 | NNW 4 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | 7 | 2 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | W 5 | SW 6 | SSW 4 | SSW 5 | SSW 6 | SW 6 | SW 4 | SW 6 | SW 6 | WSW 6 | WSW 6 | W 6 | NW 6 | WSW 4 | SW 4 | SW 6 | SW 6 | WSW 4 | WNW 5 | WNW 5 | WNW 5 |
| kJ | 48 | 26 | 37 | 85 | 122 | 142 | 52 | 141 | 216 | 333 | 249 | 152 | 96 | 16 | 19 | 162 | 94 | 25 | 69 | 64 | 87 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 44 | 244 | 179 | 231 | 437 | 221 | 316 | 319 | 167 | 319 | 506 | 596 | 333 | 282 | 256 | 44 | 506 | 262 | 338 | 381 | 173 |
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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