Surf Forecasts:
Cable Bay (Porth Trecastell) surf forecast from 21 Jul 2026:
- Most powerful swell: Saturday 25 Jul, 4PM (local time) - 2.5ft (0.8m), 4s period, WSW swell with 21 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 0.8m 4s and forecast to arrive on Saturday (Jul 25) at 4PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.5m 6s period and expected on Wednesday (Jul 22) at 7AM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 4PM (Sat 25th Jul) | 2.5ft (0.8m) 4s |
Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.
The Lowdown
G'day, Rusty here. Let’s break down what’s happening at Cable Bay (Porth Trecastell). I’ll be straight with you – this 16-day window is looking pretty bleak. There’s a long, quiet stretch ahead, and we’re not going to see any proper surf worth getting excited about. The data shows a blank run for the first few days, with nothing but poor conditions and no swell energy. It’s one of those times where the forecast just doesn’t have anything on offer for us paddle surfers.
The first few days, from Tuesday the 21st through to Thursday the 23rd of July, are a total write-off. No swell at all, just cross-off breezes and clean-looking water but no waves to ride. The water is sitting at 63°F, which is a touch warmer than normal for this time of year – about 4°F warmer than the long-term average, so that’s a bit of a treat if you’re just having a swim, but not for surfing.
Come Friday the 24th, we finally see a tiny pulse of swell – 0.3 ft from the south with a long period of 13 seconds. That’s a clean groundswell, but the energy is basically nothing (combined energy of 3). Light onshore winds spoil it, and it’s just not enough to get a wave. Same story Saturday the 25th: a bit more height, up to 3 ft on the Saturday afternoon, but it’s short-period windswell (4 seconds) and onshore wind from the southwest at 16 mph making it messy. The energy is still weak (24). Not for us.
The rest of the period, right through to Wednesday the 5th of August, is a string of flat days or ankle-biters. The highest swell we see is 1.0 ft, and that’s barely a ripple. Whiffs of swell from the SSW on the 1st and 2nd of August, with a 6-second period, but the wind is onshore or cross-on, and the energy is still very low (7 max). There’s a glassy morning on Thursday the 30th of July, and again on Saturday the 1st of August, but with no swell, it’s just a flat, calm sea.
Honestly, there are no standout days here. The best of a bad bunch might be the morning of Saturday the 1st of August – glassy conditions, a tiny 0.7 ft from the SSW with a 6-second period, but the energy is only 5. You’d be lucky to find a ripple. Don’t get your hopes up.
The water temperature anomaly is only mentioned for the first day, so I’ll leave it at that. The rest of the time, conditions are just poor. For kite surfers, the moderate onshore winds on the 25th and 26th might offer something, but for paddle surfing, it’s a no-go.
This is just one of those stretches where the forecast is a blank. It’s a bit of a bummer, but it won’t last forever – forecasts can change. Keep your eyes on the charts, and maybe dust off the longboard for a flat-day paddle. For now, I’d say save your energy.
Rusty.
Short Range ForecastMostly dry. Very mild (max 18°C on Wed afternoon, min 11°C on Tue night). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 12mm), heaviest on Sat night. Very mild (max 18°C on Fri afternoon, min 14°C on Sat morning). Wind will be generally light. | ||||||||||||||||||||
Tuesday 21 | Wednesday 22 | Thursday 23 | Friday 24 | Saturday 25 | Sunday 26 | Monday 27 | |||||||||||||||
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) | N 5 | N 5 | N 7 | NNW 6 | NNW 6 | N 6 | N 6 | N 5 | N 4 | S 13 | S 13 | WSW 3 | W 4 | WSW 4 | SW 5 | SW 6 | WNW 3 | SW 5 | SW 5 | W 3 | SW 3 |
Wave Graph  | |||||||||||||||||||||
 kJ | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 3 | 2 | 9 | 21 | 12 | 5 | 2 | 1 | 1 | 2 | 2 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-on | on | on | on | on | cross-on | cross | cross-off | cross-off | cross | cross-on | cross-on |
High Tide | 3:28PM3.18m | 3:49AM3.33m | 4:30PM3.04m | 4:56AM3.09m | 5:37PM2.97m | 6:08AM2.98m | 6:44PM3.01m | 7:16AM2.99m | 7:44PM3.13m | 8:13AM3.09m | 8:35PM3.31m | 9:01AM3.24m | 9:19PM3.52m | ||||||||
Low Tide | 9:59PM1.11m | 10:38AM1.10m | 11:03PM1.32m | 11:45AM1.31m | 00:23AM1.40m | 1:01PM1.37m | 1:39AM1.32m | 2:06PM1.28m | 2:38AM1.14m | 2:56PM1.10m | 3:23AM0.93m | 3:37PM0.90m | |||||||||
 |  |  | | | | | |  | | | |  |  |  | | | | | | | |
 | 5:16 | — | — | 5:18 | — | — | 5:18 | — | — | 5:20 | — | — | 5:22 | — | — | 5:24 | — | — | 5:24 | — | — |
 | — | — | 9:30 | — | — | 9:29 | — | — | 9:28 | — | — | 9:25 | — | — | 9:24 | — | — | 9:22 | — | — | 9:22 |
mm | — | — | — | — | — | — | — | — | — | — | — | — | 1 | — | 11 | — | — | — | — | — | — |
Temp °C | 14 | 16 | 13 | 16 | 18 | 15 | 16 | 18 | 17 | 16 | 18 | 17 | 14 | 15 | 15 | 16 | 17 | 16 | 16 | 17 | 17 |
Feels °C | 12 | 13 | 12 | 12 | 14 | 13 | 13 | 15 | 15 | 14 | 16 | 16 | 10 | 12 | 13 | 12 | 14 | 14 | 15 | 15 | 16 |
Swell 1 Height (m) Direction Period (s) | — | — | — | — | — | — | — | N 5 | N 4 | S 13 | W 3 | — | S 12 | S 12 | SW 5 | SW 6 | N 5 | SW 5 | SW 5 | N 4 | — |
| kJ | — | — | — | — | — | — | — | 18 | 3 | 3 | 1 | — | 3 | 3 | 12 | 5 | 10 | 1 | 1 | 6 | — |
Swell 2 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | NW 3 | — | SW 5 | — | — | SW 5 | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 2 | — | 1 | — | — | 1 | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | S 13 | — | — | — | S 11 | — | — | — | — | SW 5 | — |
| kJ | — | — | — | — | — | — | — | — | — | — | 3 | — | — | — | 2 | — | — | — | — | 1 | — |
Wind waves Height (m) Direction Period (s) | N 5 | N 5 | N 7 | NNW 6 | NNW 6 | N 6 | N 6 | — | — | NNW 4 | — | WSW 3 | W 4 | WSW 4 | — | NNW 5 | WNW 3 | NNW 4 | NNW 5 | W 3 | SW 3 |
| kJ | 16 | 15 | 148 | 155 | 65 | 64 | 49 | — | — | 1 | — | 2 | 9 | 21 | — | 36 | 2 | 12 | 25 | 2 | 2 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 386 | 1077 | 53 | 272 | 1078 | 277 | 277 | 294 | 287 | 302 | 880 | 261 | 381 | 381 | 393 | 393 | 574 | 260 | 178 | 244 | 256 |
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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