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 pm 17 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:

  • Most powerful swell: Thursday 20 Aug, 1AM (local time) - 3.5ft (1.1m), 6s period, SW swell with 95 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 1.1m 6s and forecast to arrive on Thursday (Aug 20) at 1AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.2m 5s period and expected on Thursday (Aug 20) at 1PM.

Wave TypeTime (BST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful 1AM (Thu 20th Aug)3.5ft (1.1m) 6s

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


The Lowdown

Right then, let's have a look at what's in store for Cable Bay over the next couple of weeks. I'll be straight with you, it's a pretty lean start. We've got a long stretch of nothing much to get excited about, with poor conditions and tiny surf hanging around for days. It’s not until the very end of the month, and into the first day of September, that we finally see a pulse of proper swell and a chance to get wet.

The first real hope shows up on Wednesday morning, the 26th of August. We've got a small increase in swell, reading 4ft from the SSW, and the energy is creeping up to a moderate 112. The real treat is the wind swinging offshore from the east, keeping things clean. But the waves will only be surfable, nothing special. The real gem comes that afternoon – the wind goes completely glassy, and the swell holds at 4ft from the same direction, with a stronger energy of 151. That's the pick of the early window, a proper clean, glassy session if you can sneak out. Water temp is sitting at 65°, which feels much warmer than usual for this time of year, so you might get away with a thinner wetsuit.

Then it gets messy again for a few days. The 27th and 28th see a jump in wind and lumpy conditions, with onshore slop. The 29th of August (Saturday) brings some size, with waves up to 6ft from the SW, but the wind is on it, making it choppy. Not worth the paddle. The 30th is a write-off with strong winds.

Now, here’s where it gets interesting. The real standout, and the only one I’d call a true highlight, comes on the 31st of August (Monday). The swell builds throughout the day, hitting a solid 10ft from the SW in the afternoon. That’s a big, powerful wave with very strong energy (1028). However, the wind is howling onshore from the southwest at 22 mph, making it a messy, expert-only affair. That's a beast of a wave, but it's a battle.

The best chance of the entire outlook actually lands on Tuesday, the 1st of September. Morning conditions see a clean 8ft swell from the WSW, with light offshore winds from the NE. The wave energy is sitting at a strong 499. This is proper, clean, powerful surf. It’s got some size though – over 8ft – so it's for experienced surfers only who know what they're doing. The wind then swings onshore in the afternoon and wrecks it, so that morning window on the 1st is your one and only golden ticket. Get on it if you can.

Keep in mind, Cable Bay (Porth Trecastell) needs that SW groundswell to work its magic, and when the wind plays ball, it can be a great little wave. The long gaps between the decent swells are tough, but that little burst at the end is worth waiting for.

Rusty.

Short Range Forecast

Moderate rain (total 14mm), heaviest on Mon night. Very mild (max 18°C on Mon night, min 14°C on Tue night). Mainly fresh winds.

Days 5-7 Weather Summary

Light rain (total 3mm), mostly falling on Thu night. Very mild (max 17°C on Sat morning, min 13°C on Thu night). Wind will be generally light.

Mon
17
Tuesday
18
Wednesday
19
Thursday
20
Friday
21
Saturday
22
Sunday
23
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
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.3
SW
5
0.8
SW
4
1
W
4
0.6
SW
6
0.9
WSW
4
1.2
WSW
5
1.2
SW
5
1.1
SW
6
0.5
SW
6
0.4
SW
6
0.1
SW
14
0.1
SW
14
0.1
SW
5
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
Wave Graph
Metric surfscale
Energy kJ
4
27
39
21
29
64
74
95
17
9
8
7
1
7
8
8
8
8
7
8
Wind (km/h)
10
W
20
WSW
25
W
15
SW
30
WSW
25
SW
30
SSW
15
W
25
NNE
25
N
10
N
15
NW
15
NE
15
NNE
10
NNE
20
N
20
N
10
N
20
N
10
ENE
Wind State
cross-on
on
cross-on
on
cross-on
on
on
cross-on
cross-off
cross-off
cross-off
cross-off
off
cross-off
off
cross-off
cross-off
cross-off
cross-off
off
High Tide
1:21AM3.95m
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
Low Tide
7:45PM0.46m
8:13AM0.53m
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
light rain
light rain
cloud
cloud
rain showers
part cloud
light rain
rain showers
rain showers
clear
rain showers
rain showers
clear
part cloud
clear
clear
clear
clear
clear
clear
<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
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
8:42
8:39
8:37
8:36
8:32
8:30
8:29
 mm
1
3
2
1
5
2
1
2
Temp °C
16
18
16
18
16
16
16
16
15
16
14
15
16
15
17
16
14
17
17
15
Feels °C
15
17
12
15
12
11
11
14
10
11
11
13
12
12
13
11
11
14
13
13
  • 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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