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 25 Aug 2026 (local time)

Forecast update in  hr  min

Today's Cable Bay (Porth Trecastell) sea temperature is
17.5°C
1.9° 

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 25 Aug 2026:

  • Most powerful swell: Monday 31 Aug, 10AM (local time) - 10ft (3.0m), 7s period, WSW swell with 705 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 3.0m 7s and forecast to arrive on Monday (Aug 31) 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 0.9m 5s period and expected on Wednesday (Aug 26) at 1AM.

Wave TypeTime (BST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful10AM (Mon 31st Aug)10ft (3.0m) 7s

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


The Lowdown

Alright mate, Rusty here. Let’s have a look at what’s cookin’ at Cable Bay for the next couple of weeks.

To be straight with you, it’s a pretty grim outlook for the majority of the window. We’ve got some energy coming through, but the wind is mostly ruining it, and the swell quality is just not there for a decent paddle. There’s a long stretch of poor conditions, especially through the back half of August and into early September. The water temp is sitting about average for the time of year, nothing unusual there.

We kick off from Tuesday the 25th of August with tiny 0.33 ft to 1 ft SSW swells. The wind is offshore or cross-off, keeping things clean, but there’s simply no size or power to work with. The combined energy is pitiful, in the single digits to low teens (7 to 17). It’s a flat spell, plain and simple.

That flatness drags on through Wednesday and Thursday. You’ll see a glassy session on Wednesday afternoon with 1 ft SSW swell and no wind, but again, tiny. Through Friday the 28th, we get a pulse of 5 ft SSW swell, but the wind swings onshore and strong from the W at 19 mph, turning it into lumpy, cross-onshore junk. The energy ticks up to 116, but the quality is zero.

The weekend and into the following week gets worse. Saturday and Sunday see increasing onshore winds, with Sunday afternoon the 30th seeing a 7 ft SSW groundswell (7-second period) and onshore winds at 22 mph, giving a combined energy of 332. It’s a messy, blown-out scene.

Then from Monday the 31st of August through Tuesday the 1st of September, it gets serious but not for surfing. We’re looking at 10 ft to 8 ft WSW to SW swell with strong to gale-force onshore winds. The combined energy hits 705 and 629. For a beach break like Cable Bay, this is all kinds of bad. The setup looks far more interesting for kite surfing than paddle surfing, honestly. It’s only for experts if they’re stupid enough to try, and even then, the wind is terrible.

Things calm down a bit through the 2nd and 3rd of September, with swell dropping back under 3 ft and some cleaner windows on the 3rd with a NNW cross-off wind. But again, tiny and unexciting.

Now, if you’re patient, there’s one standout window that might be worth the wait. On Saturday the 5th of September, the morning shows some promise. We’ve got a 5 ft WNW swell (6-second period) with a cross-off wind from the ENE at 12 mph, keeping it clean. The combined energy is a moderate 231. It’s not a huge swell, but it’s the best looking combination of size and clean conditions in the whole outlook. Crowds are possible here, so get down early.

The following Tuesday the 8th brings a very long-period groundswell (17 seconds) from the SW at 1 ft, but the energy is still low. That long period might offer a few clean lines at a point or reef, but at a beach break like this, it’ll likely break too straight to do much with. Wednesday the 9th morning has a clean, offshore 2 ft SW swell with a moderate 32 energy, but it’s small and inconsistent.

So, the honest call: the best on offer is the morning of Saturday the 5th of September with that 5 ft WNW swell and clean cross-off winds. The rest of the forecast is mostly a write-off, with a big gap of unsurfable or tiny conditions dominating the next week and a half. Keep your eye on it, but don’t hold your breath.

Rusty.

Short Range Forecast

Moderate rain (total 16mm), heaviest on Wed morning. Warm (max 21°C on Tue afternoon, min 13°C on Mon night). Wind will be generally light.

Days 4-6 Weather Summary

Heavy rain (total 58mm), heaviest during Thu night. Very mild (max 18°C on Fri night, min 15°C on Fri night). Winds increasing (light winds from the WSW on Thu night, fresh winds from the SSW by Sun afternoon).

Tuesday
25
Wednesday
26
Thursday
27
Friday
28
Saturday
29
Sunday
30
Monday
31
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
0
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.1
SW
13
0.1
SW
13
0.2
SSW
8
0.3
SSW
8
0.3
SSW
8
0.2
SSW
7
0.2
SSW
7
0.2
SSW
7
0.2
SSW
6
1.5
SSW
5
1
SSW
7
0.7
SSW
7
0.7
SW
6
0.5
SSW
6
0.6
SW
8
1.3
SSW
5
2
SSW
7
2
SW
6
3
WSW
7
1.9
WSW
6
1.1
SW
6
Wave Graph
Metric surfscale
Energy kJ
7
7
7
13
12
5
6
5
4
116
85
40
43
21
49
65
332
301
705
280
69
Wind (km/h)
20
E
15
ENE
25
E
10
E
0
NE
10
ENE
10
ESE
5
NE
20
SW
30
W
15
SW
20
W
20
S
15
SW
15
WSW
35
S
35
SSW
40
W
45
WNW
25
WSW
30
SW
Wind State
cross-off
off
cross-off
cross-off
glassy
off
cross-off
off
on
cross-on
on
cross-on
cross-on
on
on
cross-on
on
cross-on
cross-on
cross-on
on
High Tide
8:49AM3.20m
9:03PM3.55m
9:25AM3.40m
9:35PM3.81m
9:55AM3.58m
10:04PM4.02m
10:23AM3.73m
10:32PM4.18m
10:51AM3.84m
11:00PM4.28m
11:19AM3.92m
11:30PM4.30m
11:49AM3.93m
00:03AM4.23m
Low Tide
3:12PM0.93m
3:39AM0.68m
3:47PM0.67m
4:13AM0.41m
4:20PM0.46m
4:45AM0.20m
4:53PM0.30m
5:18AM0.06m
5:26PM0.21m
5:52AM0.00m
6:01PM0.20m
6:27AM0.05m
6:37PM0.27m
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cloud
light rain
rain showers
part cloud
part cloud
light rain
light rain
heavy rain
heavy rain
part cloud
rain showers
rain showers
rain showers
part cloud
rain showers
thunderstorm
rain showers
part cloud
part cloud
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<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
6:13
6:16
6:16
6:18
6:20
6:22
6:24
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
8:23
8:22
8:20
8:16
8:15
8:13
8:09
 mm
5
5
2
4
32
15
1
2
1
5
2
5
Temp °C
19
21
21
18
20
19
19
18
16
16
17
18
17
18
17
16
16
15
15
17
17
Feels °C
17
18
16
18
21
18
19
19
16
12
15
17
15
16
14
10
10
10
8
13
12
  • Map Icons:
  • Break
  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
Map placeholder
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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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