Surf Forecasts:
The Knap surf forecast from 8 Sep 2026:
- Most powerful swell: Friday 11 Sep, 7AM (local time) - 1.5ft (0.5m), 9s period, W swell with 40 kJ wave energy.
Best Forecast Surf Conditions for The Knap this week:
The most powerful waves expected at The Knap in the next 16 days are 0.5m 9s and forecast to arrive on Friday (Sep 11) at 7AM. Winds are predicted to be cross-offshore at the time the swell arrives.
| Wave Type | Time (BST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 7AM (Fri 11th Sep) | 1.5ft (0.5m) 9s |
Table - best surf conditions forecast for The Knap over the next 16 days.
Short Range ForecastModerate rain (total 10mm), heaviest on Mon night. Very mild (max 18°C on Thu morning, min 13°C on Tue night). Winds decreasing (fresh winds from the WNW on Tue afternoon, calm by Wed night). | Days 4-6 Weather SummaryLight rain (total 9mm), mostly falling on Thu night. Very mild (max 18°C on Fri afternoon, min 12°C on Fri night). Wind will be generally light. | ||||||||||||||||||||
Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | Sunday 13 | Monday 14 | |||||||||||||||
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 8 | W 5 | W 6 | W 7 | W 7 | W 8 | W 8 | WSW 5 | W 7 | W 9 | W 9 | W 8 | W 8 | W 8 | W 6 | W 8 | W 8 | W 9 | W 9 | W 9 | W 8 |
Wave Graph  | |||||||||||||||||||||
 kJ | 32 | 16 | 19 | 15 | 8 | 5 | 4 | 2 | 17 | 39 | 25 | 12 | 5 | 5 | 7 | 28 | 18 | 13 | 14 | 6 | 6 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross | cross-off | cross-off | cross-on | glassy | on | on | on | cross-off | cross | off | cross-on | cross-on | cross-on | cross | cross | glassy | cross-on | cross | glassy |
High Tide | 5:08AM9.00m | 5:38PM9.71m | 6:08AM9.86m | 6:31PM10.62m | 6:56AM10.69m | 7:16PM11.39m | 7:37AM11.34m | 7:55PM11.93m | 8:15AM11.74m | 8:33PM12.15m | 8:51AM11.86m | 9:08PM12.07m | 9:25AM11.70m | 9:42PM11.71m | |||||||
Low Tide | 11:29AM3.27m | 00:06AM2.64m | 12:26PM2.42m | 00:54AM1.81m | 1:10PM1.65m | 1:34AM1.16m | 1:47PM1.07m | 2:09AM0.73m | 2:21PM0.72m | 2:41AM0.56m | 2:54PM0.64m | 3:13AM0.64m | 3:26PM0.80m | 3:43AM0.96m | |||||||
 |  |  | | |  |  |  |  | | | | |  | | | | | | | | |
 | 6:35 | — | — | 6:37 | — | — | 6:39 | — | — | 6:39 | — | — | 6:41 | — | — | 6:43 | — | — | 6:45 | — | — |
 | — | 7:45 | — | — | 7:42 | — | — | 7:39 | — | — | 7:37 | — | — | 7:35 | — | — | 7:32 | — | — | 7:30 | — |
mm | 3 | — | — | — | — | — | — | — | 6 | — | — | — | — | 1 | 2 | — | — | — | — | — | — |
Temp °C | 16 | 17 | 15 | 16 | 17 | 14 | 18 | 18 | 16 | 16 | 18 | 14 | 16 | 17 | 17 | 18 | 18 | 18 | 21 | 21 | 18 |
Feels °C | 9 | 9 | 10 | 12 | 12 | 11 | 14 | 14 | 15 | 13 | 14 | 11 | 13 | 12 | 14 | 17 | 16 | 19 | 20 | 19 | 19 |
Swell 1 Height (m) Direction Period (s) | W 8 | — | W 8 | W 7 | W 8 | W 8 | W 8 | W 7 | W 7 | — | — | W 8 | W 8 | W 8 | W 6 | W 8 | — | W 9 | W 9 | W 9 | W 8 |
| kJ | 32 | — | 6 | 15 | 1 | 5 | 4 | 1 | 17 | — | — | 12 | 5 | 5 | 7 | 28 | — | 13 | 14 | 6 | 6 |
Swell 2 Height (m) Direction Period (s) | W 11 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | 2 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Wind waves Height (m) Direction Period (s) | — | W 5 | W 6 | — | W 7 | — | — | WSW 5 | SSW 3 | W 9 | W 9 | — | — | — | — | — | W 8 | — | — | — | — |
| kJ | — | 16 | 19 | — | 8 | — | — | 2 | 1 | 39 | 25 | — | — | — | — | — | 18 | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 61 | 353 | 135 | 53 | 126 | 69 | 201 | 219 | 102 | 53 | 40 | 14 | 69 | 165 | 165 | 53 | 85 | 39 | 153 | 165 | 68 |
Best forecast wave conditions in Wales - South East | |||||||||||||||||||||
Best forecast wave conditions in United Kingdom | |||||||||||||||||||||
Header Global | |||||||||||||||||||||
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FREE! Surf-Forecast.com widget for your website
The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our The Knap surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.
Information about the The Knap Surf forecast
The above surf forecast table for The Knap provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at The Knap can be found by selecting the local surf guide option on the grey menu. Our The Knap 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 (The Knap) 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 The Knap 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.
The Knap is 2 km (1 miles) from Barry. If you plan a holiday in Wales - South East, look for hotels and other accommodation in Barry. Barry has rooms for a wide range of budgets as well as car hire and transport links.
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