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 09 Aug 2026 (local time)

Forecast update in  hr  min

Today's Cable Bay (Porth Trecastell) sea temperature is
17.1° C
1.5° 

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 9 Aug 2026:

  • Most powerful swell: Friday 14 Aug, 4AM (local time) - 2ft (0.6m), 5s period, SW swell with 17 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 0.6m 5s and forecast to arrive on Friday (Aug 14) at 4AM. Winds are predicted to be glassy at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.0m 5s period and expected on Saturday (Aug 15) at 10AM.

Wave TypeTime (BST) & Date Wave Height & Period
Next good surf (1 star+)--
Best Surf--
Most Powerful 4AM (Fri 14th Aug)2ft (0.6m) 5s

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


The Lowdown

Alright, let’s get this straight. The next couple of weeks are looking pretty bleak for a proper surf. We’ve got a whole lot of nothing on the horizon, with a long stretch of flat, unrideable conditions. But, hold on, there is a flicker of hope right at the very end of the forecast period. It’s going to be a test of patience, that’s for sure.

The wait is the story here. From now through the next several days, we're staring down a blank canvas. Swell heights are barely registering, with the ocean mostly at 0.3ft or even less. The energy is just pathetic, with values often in the single digits, like 10 or even 1. There are a few pulses around the 11th and 12th, but they're weak and messy with onshore winds, so it’s not worth getting excited about.

We’ll see a little bump on the 14th with some 2ft swell and a period of 4 seconds, but it's crossed up. Then the 17th and 18th offer a touch more size—up to 3.3ft—but the wind turns onshore and the energy is still on the low side at 32 and 49. It’s all just poor surf conditions. Honestly, for a spot like this, a run of flat days isn't unusual, but this feels like a longer draught than normal.

Then, as we look to the end of the window, things might finally start to align. From the 20th onwards, we see a pulse of new energy and the winds finally turn favorable. On the 20th and 21st, the swell is pushing 3.6ft to 4.3ft from the WNW with periods hanging around 5 seconds. It’s not going to be epic, but the energy values are climbing, hitting 69 and then 96, which is a healthy kick. The winds turn cross-off and then offshore, which is exactly what we want to hear. The 21st afternoon should finally see some surfable waves, even if they’re ordinary. The water temp is still about average for the time of year, 62.8°F.

Cable Bay (Porth Trecastell) is the only game in town, and this is where the focus should be. It’s exposed to that SW swell, which is what we’re getting. The standout is Friday the 21st. The swell is 4.3ft from the WNW, and with a 9 mph offshore wind from the NE, it's going to be clean and lined up. This is the one to circle on the calendar. The energy value of 96 is by far the most promising we see in the entire period. This is your window. It’s a long way off, so treat it as promising, not guaranteed.

After that, the energy fades again, but there’s a glassy morning on the 22nd and 23rd, though the swell drops right back down. If you can only get out once, make it the 21st afternoon.

Short Range Forecast

Mostly dry. Warm (max 22°C on Tue afternoon, min 13°C on Sun night). Wind will be generally light.

Days 5-7 Weather Summary

Mostly dry. Warm (max 24°C on Wed afternoon, min 13°C on Sat morning). Wind will be generally light.

Sun
9
Monday
10
Tuesday
11
Wednesday
12
Thursday
13
Friday
14
Saturday
15
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)
0.1
SW
12
0.4
SSW
4
0.4
SW
6
0.3
SW
6
0.2
SSW
6
0.2
SSW
6
0.1
SW
6
0.1
S
11
0.1
SW
12
0.1
SW
12
0.1
SW
10
0.1
SW
11
0.1
SW
11
0.6
SW
4
0.6
WNW
4
0.5
NW
4
0.1
SW
6
0.1
W
8
0.1
SW
7
0.1
SW
7
Wave Graph
Metric surfscale
Energy kJ
6
7
8
5
4
4
1
2
5
6
4
5
4
16
10
7
2
1
2
2
Wind (km/h)
20
SSW
15
N
10
NNW
15
NNW
15
ENE
5
S
15
SW
10
SSE
15
S
10
WSW
10
SSE
10
SSW
10
WNW
10
S
20
NW
15
NNW
15
N
25
NNW
25
NNW
15
N
Wind State
on
cross-off
cross-off
cross-off
off
cross-on
on
cross
cross-on
cross-on
cross-on
cross-on
cross-on
cross-on
cross
cross-off
cross-off
cross-off
cross-off
cross-off
High Tide
7:10PM3.38m
7:48AM3.43m
8:14PM3.71m
8:49AM3.66m
9:07PM4.05m
9:40AM3.86m
9:54PM4.35m
10:25AM4.00m
10:38PM4.54m
11:07AM4.05m
11:19PM4.59m
11:46AM4.02m
00:00AM4.50m
Low Tide
2:14AM0.73m
2:42PM0.68m
3:13AM0.33m
3:34PM0.38m
4:04AM-0.04m
4:20PM0.13m
4:50AM-0.29m
5:04PM-0.02m
5:34AM-0.40m
5:45PM-0.06m
6:15AM-0.35m
6:25PM0.02m
part cloud
part cloud
clear
part cloud
part cloud
clear
clear
part cloud
clear
clear
clear
clear
part cloud
part cloud
part cloud
clear
part cloud
cloud
clear
clear
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
5:48
5:50
5:52
5:52
5:54
5:56
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
8:58
8:57
8:54
8:52
8:50
8:47
8:45
 mm
Temp °C
18
15
16
16
16
21
22
21
22
24
22
23
23
21
17
19
17
14
15
14
Feels °C
15
12
13
13
13
17
19
20
18
21
20
23
23
22
15
17
15
9
10
11
  • 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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