Cable Bay (Porth Trecastell) Surf Break

Lat Long: 53.22° N 4.51° W

Cable Bay (Porth Trecastell) Surf Forecast and Surf Report

Issued: 6 am 18 Aug 2026 (local time)

Forecast update in  hr  min

Today's Cable Bay (Porth Trecastell) sea temperature is
18.1° C
2.3° 

Cable Bay (Porth Trecastell) surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.


Cable Bay (Porth Trecastell) surf forecast from 18 Aug 2026:

  • Best quality surf: Tuesday 25 Aug, 1AM (local time) - 6ft (1.8m), 6s period, S swell with cross-offshore winds.
  • Most powerful swell: Tuesday 25 Aug, 10AM (local time) - 4.5ft (1.4m), 8s period, SSW swell with 245 kJ wave energy.
  • Next surfable swell (1★+): Monday 24 Aug, 7PM (local time) - 4.5ft (1.3m), 5s period with SSW swell.

Best Forecast Surf Conditions for Cable Bay (Porth Trecastell) this week:

The surf forecast for Cable Bay (Porth Trecastell) over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Monday (Aug 24) at 7PM. The primary swell is predicted to be 1.3m and 5s period with a secondary swell of 0.1m and 13s. The wind is predicted to be glassy as the swell arrives.

The most powerful waves expected at Cable Bay (Porth Trecastell) in the next 16 days are 1.4m 8s and forecast to arrive on Tuesday (Aug 25) at 10AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.7m 6s period and expected on Thursday (Aug 20) at 1PM.

Wave TypeTime (BST) & Date Wave Height & Period
Next good surf (1 star+) 7PM (Mon 24th Aug)4.5ft (1.3m) 5s
Best Surf 1AM (Tue 25th Aug)6ft (1.8m) 6s
Most Powerful10AM (Tue 25th Aug)4.5ft (1.4m) 8s

Table - best surf conditions forecast for Cable Bay (Porth Trecastell) over the next 16 days.


The Lowdown

Alright folks, Rusty here. Let’s be straight with you: the next couple of weeks at Cable Bay (Porth Trecastell) are looking pretty grim for anyone wanting to paddle out and actually catch something. We’ve got a whole lot of nothing on offer for the start of this stretch, and I mean a whole lot.

We’re looking at a solid run of poor surf through the coming week and into the next. The swell is mostly tiny, weak, and coming from the wrong direction for this spot. The wave energy is barely registering, mostly two-digit numbers like 48 or 74, which just tells you there’s nothing behind those waves at all. There are some clean, glassy moments early on the morning of Friday the 21st, with a slight air and a glassy surface, but the swell is only 0.7ft. You could paddle out on a log and not get wet. It’s frustrating, but that’s the way it is.

We will see a bit more energy kick in around Tuesday the 25th, with the swell pushing up to 5ft. The energy jumps to around 105, but it’s still cross-onshore, choppy, and basically unsurfable. The wind is going to mess it up. That pattern holds for a few days – a bit of size, but with the wind all over it, so it’s a mess.

Now, if you’re looking for something that *might* be worth a look, you’ve got to wait until Saturday the 29th or Sunday the 30th. Saturday sees the swell jump to 7ft with the energy jumping to 352 (moderate wave energy), but again, the wind is cross-onshore and it’s going to be choppy. Not great. Then on Sunday the 30th, there’s a brief moment where the wind dies down a bit to a light breeze. The swell is still around 4ft, and the energy is at 107. It’s still cross-onshore and there’ll be some small wind ripples, but it’s the first time the conditions aren’t a total write-off. It’s a marginal call though, so don’t get too excited.

The real, and I mean the *only* standout in this whole 16-day window, looks like it’s on Monday the 31st. The swell is up to 8ft, and the wave energy is cranking – we’re talking 712 to 824 (strong to very strong wave energy). That’s a proper pulse of west-southwest swell. The problem is, it’s still cross-onshore, so it’s going to be a bit of a battle. This size is pushing past what I’d call beginner territory, and with that wind, it’ll be one for the experienced crew only. It’s a "promising but less certain" call this far out, but it’s the only time we see any real power in the water.

The first week of September doesn’t offer much to get excited about either. A bit of size but the wind stays on it, keeping things messy.

So, bottom line? For the next couple of weeks, Cable Bay isn't your friend. If you're desperate, you might get a session in on that Sunday the 30th, but you’ll be scratching around. If you’re experienced and don’t mind a battle, keep an eye on the 31st. Otherwise, keep the board in the car and wait for a change in the forecast. This long blank run is just how it goes around here sometimes.

Rusty, out.

Short Range Forecast

Moderate rain (total 13mm), heaviest on Thu morning. Very mild (max 17°C on Tue afternoon, min 12°C on Thu night). Wind will be generally light.

Days 4-6 Weather Summary

Mostly dry. Very mild (max 16°C on Fri afternoon, min 12°C on Fri night). Wind will be generally light.

Tuesday
18
Wednesday
19
Thursday
20
Friday
21
Saturday
22
Sunday
23
Monday
24
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.6
SW
6
0.6
SW
6
0.9
WSW
4
0.9
WSW
4
0.8
SW
4
0.9
SW
6
0.5
SW
6
0.3
SW
6
0.1
SW
14
0.1
SW
14
0.1
SW
13
0.1
SW
13
0.1
SW
15
0.1
SW
15
0.1
SW
15
0.1
SW
14
0.1
SW
14
0.1
SW
14
0.9
SSW
4
1.1
SSW
5
1.8
S
6
Wave Graph
Metric surfscale
Energy kJ
32
21
21
25
20
47
16
8
8
7
7
7
8
8
8
8
7
8
22
54
243
Wind (km/h)
25
W
15
WSW
20
WSW
25
WSW
25
SSW
15
W
20
N
25
NNE
15
NNE
10
NNE
10
NNW
15
N
15
NNW
20
NNW
15
NNW
15
NNW
15
NNW
10
ENE
10
S
15
WSW
5
E
Wind State
cross-on
on
on
cross-on
on
cross-on
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
cross-off
off
cross-on
on
cross-off
High Tide
1:44PM3.51m
2:05AM3.58m
2:29PM3.25m
2:56AM3.21m
3:26PM3.00m
4:05AM2.90m
4:46PM2.83m
5:38AM2.76m
6:19PM2.84m
7:04AM2.82m
7:32PM3.02m
8:05AM2.99m
8:24PM3.28m
Low Tide
8:25PM0.77m
8:54AM0.92m
9:10PM1.10m
9:40AM1.27m
10:08PM1.38m
10:45AM1.54m
11:34PM1.55m
12:20PM1.61m
1:12AM1.48m
1:41PM1.46m
2:17AM1.25m
2:33PM1.20m
3:02AM0.96m
part cloud
cloud
rain showers
part cloud
part cloud
rain showers
rain showers
part cloud
part cloud
cloud
part cloud
part cloud
part cloud
cloud
part cloud
cloud
clear
clear
clear
clear
part cloud
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
6:01
6:03
6:05
6:07
6:09
6:11
6:11
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
8:39
8:37
8:36
8:32
8:30
8:29
8:27
 mm
3
5
5
Temp °C
16
17
15
16
16
15
15
16
14
14
16
14
14
15
14
14
14
14
16
17
17
Feels °C
12
14
11
12
11
13
12
11
11
11
14
11
10
11
12
12
11
12
13
14
15
  • Map Icons:
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  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
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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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