Cable Bay (Porth Trecastell) Surf Break

Lat Long: 53.22° N 4.51° W

Cable Bay (Porth Trecastell) Surf Forecast and Surf Report

Issued: 12 am 29 Aug 2026 (local time)

Forecast update in  hr  min

Today's Cable Bay (Porth Trecastell) sea temperature is
17.8°C
2.2° 

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 29 Aug 2026:

  • Most powerful swell: Saturday 5 Sep, 4AM (local time) - 7ft (2.1m), 8s period, SW swell with 481 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 8s and forecast to arrive on Saturday (Sep 05) at 4AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.5m 5s period and expected on Monday (Aug 31) at 7PM.

Wave TypeTime (BST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful 4AM (Sat 5th Sep)7ft (2.1m) 8s

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


The Lowdown

Righto, let’s have a look at what’s coming up for Cable Bay (Porth Trecastell). It’s gonna be a rough stretch, I won’t sugar-coat it. The whole sixteen-day window looks pretty bleak for a proper surf, with long gaps of nothing really rideable. The water temp is about average for this time of year, so no surprises there.

We start off on Saturday the 29th of August, and honestly, it’s a write-off. Tiny little 3ft swell from the SSW with a short, weak period of 6 seconds and combined energy of only 44 – that’s barely a ripple. Light cross-shore wind, but the waves are just too weak and poor. That sets the tone for the next several days. It’s a real flat spell through the end of August and into the first few days of September. There’s a bit of a bump on Monday the 31st with the swell hitting 5ft and energy jumping to 239, but it’s from the WNW with a short 6-second period and a fresh cross-shore wind ruining it. All poor, all scores of zero.

The first and only real standout, if you can call it that, comes on the 5th of September. Saturday afternoon shows a solid 8ft swell from the SSW with a combined energy of 531 – that’s moderate to strong, so there’s some grunt in the water. The period is still short at 7 seconds, though, so it’ll be a bit lumpy and less consistent than a longer-period groundswell. With the swell this big – over 5ft – it’s not for beginners, and it’s pushing expert territory. The wind is light onshore from the SW, which is a shame, but the energy is there. It’s only marked as a marginal call with a score of 2, so don’t expect perfection. The break is exposed to the SW, which matches the swell direction, so it’ll be picking up that energy. For a spot that’s fairly consistent, this is the one window where it might just be worth a paddle.

After that, the swell drops away again. Sunday the 6th of September afternoon sees a drop to 5ft from the SW, but with a light cross-off breeze from the NNE, the surf forecast actually looks “good” with a score of 2. It’s clean, but the period is still short at 6 seconds, and the energy is down to 215. That’s your second-best shot. Then it’s back to poor conditions through the second week, with messy onshore winds and weak, short-period swells. There’s a spike on Friday the 11th of September with a 6ft swell and strong energy of 637, but it’s onshore wind from the SW and the forecast is poor – just messy and lumpy. After that, it’s tiny again, with nothing worth mentioning through to the 13th.

So overall, if you’re itching for something, aim for the 5th or 6th of September. The rest of the time, you’re better off leaving the board at home. The crowds at Cable Bay can be *sometimes* a thing, but honestly, with this outlook, you’ll likely have the place to yourself.

Rusty.

Short Range Forecast

Moderate rain (total 10mm), heaviest on Sat morning. Very mild (max 17°C on Fri night, min 13°C on Mon morning). Winds increasing (light winds from the WSW on Sat night, fresh winds from the S by Sun afternoon).

Days 4-6 Weather Summary

Light rain (total 8mm), mostly falling on Wed afternoon. Very mild (max 18°C on Tue afternoon, min 15°C on Mon night). Winds increasing (calm on Tue night, strong winds from the SW by Wed afternoon).

Saturday
29
Sunday
30
Monday
31
Tuesday
1
Wednesday
2
Thursday
3
Friday
4
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
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.8
SSW
6
0.7
SSW
6
1
SSW
9
0.6
SW
8
1.4
SSW
6
1.1
SW
7
1.5
WNW
6
0.6
SW
8
0.9
SW
5
1.3
SW
6
0.9
SSW
6
0.7
SW
6
0.9
SSW
6
1.8
SSW
6
1.8
SW
7
1.7
WSW
5
1.1
WSW
5
1.2
W
5
1.1
WSW
5
0.9
SSW
5
2.1
SW
8
Wave Graph
Metric surfscale
Energy kJ
44
33
165
57
126
136
138
48
42
111
53
34
45
254
316
157
66
66
61
44
469
Wind (km/h)
10
SSE
15
NNE
10
WSW
25
S
35
S
15
WSW
35
NW
15
SW
20
SW
30
SW
30
SW
0
NE
25
S
35
S
35
W
35
W
30
WSW
30
WSW
35
WSW
25
WSW
35
WNW
Wind State
cross
cross-off
cross-on
cross-on
cross-on
cross-on
cross
on
on
on
on
glassy
cross-on
cross-on
cross-on
cross-on
on
cross-on
on
on
cross-on
High Tide
10:51AM3.84m
11:00PM4.28m
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
Low Tide
5:18AM0.06m
5:26PM0.21m
5:52AM0.00m
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
light rain
rain showers
part cloud
light rain
thunderstorm
part cloud
part cloud
cloud
part cloud
rain showers
light rain
rain showers
part cloud
rain showers
rain showers
clear
cloud
cloud
cloud
cloud
part cloud
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
6:20
6:22
6:24
6:26
6:28
6:30
6:31
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
8:15
8:13
8:09
8:07
8:06
8:02
8:00
 mm
3
1
3
3
1
1
1
3
2
Temp °C
16
16
15
17
17
15
15
16
17
16
18
16
17
18
17
15
17
16
15
17
15
Feels °C
15
15
14
13
12
12
10
12
14
11
15
16
12
13
12
8
11
11
9
12
8
  • Map Icons:
  • Break
  • 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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