Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 12 Aug 2026:
- Most powerful swell: Wednesday 19 Aug, 10AM (local time) - 5.5ft (1.7m), 6s period, WNW swell with 173 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 1.7m 6s and forecast to arrive on Wednesday (Aug 19) at 10AM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 5s period and expected on Sunday (Aug 16) at 4AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 10AM (Wed 19th Aug) | 5.5ft (1.7m) 6s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
Alright, this is Rusty, and I’m lookin’ at the outlook for Cable Bay (Porth Trecastrell) right here. To be straight with you, the next week and a half is a bit of a struggle. We’ve got a long stretch of tiny, weak swells and poor conditions. The first real chance of anything worth paddling out for doesn’t show up until the morning of August 19th, and even then it’s just gettin’ started. From August 12th all the way through the 18th, it’s mostly flat to knee-high junk with a lot of cross-onshore wind and choppy water. The water temperature is 64°, which is a touch warmer than normal for this time of year, so you won’t be shiverin’ too much, but there’s no surf to enjoy it in.
The first hint of life comes on Wednesday morning, August 19th. The swell jumps to 6ft out of the WNW, with a combined energy of 183 (moderate) and light onshore winds. It’s not clean, but it’s the first sign of energy. Then the standout window opens up on Thursday morning, August 20th. That’s the one to circle. We’ve got a 6ft swell from the NW, a solid 6-second period, and a combined energy of 264 (moderate). The wind is out of the NE (offshore), and it’s clean. That’s gonna produce some proper, rideable waves. The size is solid for intermediate surfers, but at 6ft it’s gonna be a bit much for beginners. The swell direction (NW) is perfect for this exposed SW-facing spot, so the lines should be decent. It’s a fairly consistent break, so expect a few others in the water—crowds are possible here.
After that, the surf fades fast. The rest of the 20th drops off, and from the 21st through the 27th it’s back to tiny, weak swell with clean conditions but no power. The only other flicker is on Monday morning, August 24th, when a 4ft SSW swell rolls in with a 7-second period and 128 energy (moderate), but it’s just ordinary. The wind is clean, but the waves lack the punch of that Thursday morning.
So, the clear winner is Thursday morning, August 20th. That’s your best bet for some real waves—offshore wind, solid chest-to-head-high swell, and moderate energy. The rest of the window is a flat spell of small, weak junk. If you’re desperate, the 24th offers a little something, but it’s not the same.
Rusty.
Short Range ForecastMostly dry. Warm (max 27°C on Wed afternoon, min 14°C on Fri night). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 15mm), heaviest on Mon morning. Very mild (max 17°C on Mon afternoon, min 13°C on Sat night). Mainly fresh winds. | ||||||||||||||||||||
Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | |||||||||||||||
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 12 | SW 12 | SW 10 | SW 11 | SW 11 | SW 5 | NW 4 | NW 4 | SSW 6 | SW 6 | SW 6 | SW 6 | NNW 5 | W 7 | W 7 | SSW 2 | S 4 | SSW 5 | SW 6 | SSW 4 | SW 6 |
Wave Graph  | |||||||||||||||||||||
 kJ | 6 | 6 | 4 | 5 | 4 | 26 | 7 | 5 | 3 | 1 | 2 | 1 | 0 | 1 | 1 | 1 | 27 | 20 | 10 | 26 | 46 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | on | on | cross-on | cross-on | cross-off | cross-off | cross-off | cross | cross-off | cross-off | cross-off | cross-on | cross-on | cross-on | cross | cross-on | on | on |
High Tide | 9:54PM4.35m | 10:25AM4.00m | 10:38PM4.54m | 11:07AM4.05m | 11:19PM4.59m | 11:46AM4.02m | 00:00AM4.50m | 12:25PM3.91m | 00:40AM4.27m | 1:04PM3.73m | 1:21AM3.95m | 1:44PM3.51m | 2:05AM3.58m | ||||||||
Low Tide | 4:20PM0.13m | 4:50AM-0.29m | 5:04PM-0.02m | 5:34AM-0.40m | 5:45PM-0.06m | 6:15AM-0.35m | 6:25PM0.02m | 6:55AM-0.16m | 7:05PM0.20m | 7:34AM0.15m | 7:45PM0.46m | 8:13AM0.53m | 8:25PM0.77m | ||||||||
 |  |  | | | |  | |  | | | | | |  |  |  |  | | |  | |
 | 5:52 | — | — | 5:52 | — | — | 5:54 | — | — | 5:56 | — | — | 5:58 | — | — | 6:00 | — | — | 6:01 | — | — |
 | — | 8:52 | — | — | 8:50 | — | — | 8:47 | — | — | 8:45 | — | — | 8:44 | — | — | 8:42 | — | — | 8:39 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 1 | 12 | 1 | 1 | — | — | 14 |
Temp °C | 24 | 27 | 25 | 22 | 22 | 19 | 17 | 17 | 16 | 15 | 16 | 15 | 14 | 16 | 15 | 16 | 17 | 17 | 16 | 18 | 18 |
Feels °C | 21 | 25 | 24 | 20 | 22 | 17 | 16 | 15 | 13 | 10 | 12 | 12 | 10 | 14 | 14 | 14 | 16 | 13 | 12 | 15 | 17 |
Swell 1 Height (m) Direction Period (s) | SW 12 | SSW 3 | SW 10 | SW 8 | SW 8 | SW 5 | SW 4 | NW 4 | SSW 6 | SW 6 | SW 6 | SW 6 | — | W 7 | NNW 4 | N 4 | — | SSW 5 | SW 6 | — | SW 6 |
| kJ | 6 | 2 | 4 | 3 | 2 | 26 | 7 | 3 | 3 | 1 | 2 | 1 | — | 1 | 3 | 1 | — | 20 | 10 | — | 46 |
Swell 2 Height (m) Direction Period (s) | S 6 | SW 12 | — | SW 5 | SW 11 | S 11 | — | SW 5 | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | 1 | 6 | — | 1 | 4 | 2 | — | 3 | — | — | — | — | — | — | — | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | W 10 | SW 6 | — | SW 11 | S 11 | — | — | N 4 | — | — | — | — | — | — | W 7 | — | — | — | — | — | — |
| kJ | 2 | 1 | — | 5 | 2 | — | — | 2 | — | — | — | — | — | — | 1 | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | SSW 3 | — | SSW 5 | SW 3 | SSW 2 | SW 5 | NW 4 | NW 4 | N 4 | NNW 4 | NNW 4 | N 4 | NNW 5 | NNW 5 | — | SSW 2 | S 4 | — | — | SSW 4 | WNW 4 |
| kJ | 3 | — | 3 | 1 | 1 | 26 | 6 | 5 | 5 | 21 | 13 | 18 | 31 | 17 | — | 1 | 27 | — | — | 26 | 19 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 227 | 158 | 158 | 173 | 258 | 185 | 187 | 558 | 333 | 613 | 596 | 287 | 287 | 295 | 297 | 302 | 307 | 173 | 297 | 302 | 105 |
Best forecast wave conditions in Anglesy | |||||||||||||||||||||
Best forecast wave conditions in United Kingdom | |||||||||||||||||||||
Header Global | |||||||||||||||||||||
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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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