Surf Forecasts:
Crab Island surf forecast from 17 Aug 2026:
- Best quality surf: Thursday 20 Aug, 7PM (local time) - 3.5ft (1.1m), 6s period, WNW swell with offshore winds.
- Most powerful swell: Thursday 20 Aug, 1AM (local time) - 6ft (1.8m), 8s period, WSW swell with 406 kJ wave energy.
- Next surfable swell (1★+): Thursday 20 Aug, 7PM (local time) - 3.5ft (1.1m), 6s period with WNW swell.
Best Forecast Surf Conditions for Crab Island this week:
The surf forecast for Crab Island over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Thursday (Aug 20) at 7PM. The primary swell is predicted to be 1.1m and 6s period with a secondary swell of 0.9m and 6s. Another secondary swell of 0.5m and 9s is also forecast. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Crab Island in the next 16 days are 1.8m 8s and forecast to arrive on Thursday (Aug 20) at 1AM. 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 3s period and expected on Sunday (Aug 23) at 7PM.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 7PM (Thu 20th Aug) | 3.5ft (1.1m) 6s |
| Best Surf | 7PM (Thu 20th Aug) | 3.5ft (1.1m) 6s |
| Most Powerful | 1AM (Thu 20th Aug) | 6ft (1.8m) 8s |
Table - best surf conditions forecast for Crab Island over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a look at what’s coming down the line for Crab Island. It’s a reef setup, fairly consistent, and it loves a good SW swell. Right now, though, we’ve got a bit of a flat spell to get through.
The outlook starts this Monday, the 17th of August, and honestly, the first week is a write-off. We’re talking about a string of days with poor surf conditions and tiny waves. Monday morning has a weak 2ft west swell with a short 6 second period and combined energy of only 26. It’s clean, but there’s just no power. The whole week through to the 23rd sees nothing but knee-high slop at best, with the swell energy barely cracking 100. The wind is mostly cross or cross-off, which keeps things tidy, but there’s simply nothing to ride. This is a real dry spell.
We get a slight tease on the morning of the 30th of August. The swell picks up a little to 4ft from the WSW, with a 6 second period and energy at 154. The wind goes glassy, so it’ll be clean as a whistle, and the conditions are described as “surfable.” It’s not great, but it’s something. The afternoon of the 30th sees a 5ft WSW swell and clean offshore winds, but the energy is still only moderate at 192. It’s ordinary, but it’s a start.
Now, the real standout is lurking a week away, on the 27th of August. The Thursday morning sees a solid 8ft WSW groundswell, with a 10 second period. The combined energy is a beefy 1219 (strong wave energy). The wind is a clean, cross-off from the WNW, so the reef at Crab Island should be holding some proper, powerful lines. The only caveat is that this is a serious step up in size. At 8ft, that’s expert territory, so only the experienced crew should be looking at this. The afternoon of the 27th is still a chunky 8ft, but the wind swings cross-shore and gets lumpy, so the morning is the clear window.
The 26th of August afternoon is worth a mention too, with a 6ft SW swell and a 7 second period, but the energy is a strong 582. The wind is cross-off, making it clean. It’s a smaller, more manageable option for the strong intermediates, but the 27th morning is the one to circle on the calendar. That’s the pick of the whole 16-day window.
Keep in mind that the water temperature anomaly is about average for the time of year, so no surprises there.
So, to sum it up: a long, flat first week is a total bust. The 30th of August offers a tiny, glassy session for the desperate. The real gold is on the 27th of August morning, with a big, clean, powerful WSW swell. Set your alarms for that one, but don’t be a hero if you’re not ready for the size.
Stay stoked,
Rusty.
Short Range ForecastLight rain (total 6mm), mostly falling on Wed night. Very mild (max 19°C on Mon morning, min 14°C on Wed night). Winds increasing (light winds from the WNW on Mon morning, fresh winds from the WSW by Wed afternoon). | Days 4-6 Weather SummaryLight rain (total 5mm), mostly falling on Thu afternoon. Very mild (max 18°C on Thu afternoon, min 13°C on Thu night). Wind will be generally light. | ||||||||||||||||||||
Monday 17 | Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | |||||||||||||||
AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | |
Swell Height Map | |||||||||||||||||||||
Wave Height (m) Direction Period (s) | W 6 | W 6 | WSW 7 | W 7 | W 6 | WSW 6 | WSW 7 | WSW 7 | WSW 8 | WSW 7 | W 7 | WSW 9 | W 8 | WSW 8 | WSW 9 | WSW 10 | WSW 10 | WSW 9 | WSW 9 | WSW 9 | WSW 9 |
Wave Graph | |||||||||||||||||||||
30 | 40 | 54 | 104 | 94 | 101 | 186 | 239 | 406 | 186 | 111 | 25 | 36 | 22 | 15 | 19 | 19 | 17 | 16 | 16 | 8 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross | cross-on | cross-off | cross | cross | cross | cross | cross | cross-off | cross | off | glassy | cross-off | off | cross-off | cross-off | off | off | cross-off | off |
High Tide | 10:10AM9.04m | 10:23PM9.02m | 10:41AM8.59m | 10:55PM8.48m | 11:12AM8.06m | 11:28PM7.89m | 11:51AM7.51m | 00:13AM7.29m | 12:49PM7.00m | 1:23AM6.79m | 2:19PM6.75m | 2:58AM6.69m | 3:48PM7.01m | ||||||||
Low Tide | 4:04PM1.48m | 4:25AM1.75m | 4:35PM1.94m | 4:54AM2.27m | 5:08PM2.48m | 5:28AM2.83m | 5:52PM3.08m | 6:17AM3.42m | 7:01PM3.61m | 7:43AM3.84m | 8:36PM3.79m | 9:21AM3.79m | 10:00PM3.49m | ||||||||
6:03 | — | — | 6:05 | — | — | 6:05 | — | — | 6:07 | — | — | 6:09 | — | — | 6:11 | — | — | 6:13 | — | — | |
— | 8:35 | — | — | 8:32 | — | — | 8:30 | — | — | 8:29 | — | — | 8:27 | — | — | 8:24 | — | — | 8:22 | — | |
mm | — | — | — | — | — | — | — | 2 | 4 | — | 4 | 1 | — | — | — | — | — | — | — | — | — |
Temp °C | 19 | 19 | 18 | 19 | 18 | 17 | 17 | 17 | 16 | 16 | 18 | 16 | 15 | 17 | 14 | 17 | 18 | 16 | 17 | 20 | 15 |
Feels °C | 16 | 15 | 16 | 15 | 14 | 14 | 11 | 11 | 11 | 13 | 16 | 15 | 13 | 14 | 10 | 15 | 14 | 13 | 15 | 16 | 11 |
Swell 1 Height (m) Direction Period (s) | W 6 | W 8 | — | W 7 | SW 17 | SW 17 | SW 16 | — | SW 16 | WSW 7 | W 7 | W 6 | W 8 | WSW 8 | WSW 9 | WSW 10 | WSW 10 | WSW 9 | WSW 9 | WSW 9 | WNW 4 |
30 | 6 | — | 104 | 11 | 12 | 11 | — | 10 | 186 | 110 | 22 | 36 | 22 | 15 | 19 | 19 | 17 | 16 | 16 | 2 | |
Swell 2 Height (m) Direction Period (s) | W 7 | W 18 | — | SW 16 | — | — | — | — | SW 16 | SW 15 | SW 14 | WSW 9 | SW 16 | SW 13 | NW 3 | SW 15 | SW 15 | SW 15 | SW 14 | SW 14 | WSW 9 |
4 | 6 | — | 11 | — | — | — | — | 10 | 8 | 8 | 25 | 10 | 7 | 2 | 9 | 8 | 8 | 8 | 8 | 8 | |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | SW 14 | SW 14 | SW 13 | SW 16 | W 11 | — | — | — | — | — | SW 14 |
— | — | — | — | — | — | — | — | — | — | 8 | 8 | 7 | 10 | 2 | — | — | — | — | — | 8 | |
Wind waves Height (m) Direction Period (s) | — | W 6 | WSW 7 | — | W 6 | WSW 6 | WSW 7 | WSW 7 | WSW 8 | — | W 7 | NW 4 | — | — | — | — | — | NW 3 | — | W 2 | — |
— | 40 | 54 | — | 94 | 101 | 186 | 239 | 406 | — | 111 | 4 | — | — | — | — | — | 2 | — | 1 | — | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 427 | 450 | 361 | 144 | 691 | 399 | 416 | 368 | 64 | 20 | 1 | 7 | 15 | 319 | 319 | 253 | 307 | 51 | 86 | 395 | 319 |
Best forecast wave conditions in Wales - Gower | |||||||||||||||||||||
Best forecast wave conditions in United Kingdom | |||||||||||||||||||||
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Information about the Crab Island Surf forecast
The above surf forecast table for Crab Island provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Crab Island can be found by selecting the local surf guide option on the grey menu. Our Crab Island 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 (Crab Island) 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 Crab Island 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.
Crab Island is 8 km (5 miles) from Swansea. If you plan a holiday in Wales - Gower, look for hotels and other accommodation in Swansea. Swansea has rooms for a wide range of budgets as well as car hire and transport links.











