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The Knap Surf Forecast
/ Wales – South East (14 surf breaks) /
Surf Forecasts:
The Knap surfForecast / Wales – South East / UK
48hr Weather and Surf, issued 6 pm Wednesday 17 Sep 2025 BST
How big are the waves at The Knap today?
The current surf forecast for The Knap at 1AM is: 0.7m 12s primary swell from a West direction (forecast issued at 06:00pm September 17). The wind direction is predicted to be cross-onshore.
| Time (BST) & Date | Wave Height | Wave Period |
|---|---|---|
| Morning (18 Sep) | 2ft (0.6m) | 12s |
| Afternoon (18 Sep) | 1.5ft (0.5m) | 11s |
| Evening (18 Sep) | 1.5ft (0.5m) | 11s |
Table - waves today at The Knap. (Swell directed towards the surf break)
Wednesday 17 | Thursday 18 | Friday 19 | Saturday 20 | |||||||||||||||||||||
| 4 PM | 7 PM | 10 PM | 1 AM | 4 AM | 7 AM | 10 AM | 1 PM | 4 PM | 7 PM | 10 PM | 1 AM | 4 AM | 7 AM | 10 AM | 1 PM | 4 PM | 7 PM | 10 PM | 1 AM | 4 AM | 7 AM | 10 AM | 1 PM | |
Rating (10 max) | ||||||||||||||||||||||||
Swell Height Map |    |    |    |    | ||||||||||||||||||||
| Wave Height (m) & direction (?) | ||||||||||||||||||||||||
| Period(s) (?) | 10 | 10 | 11 | 12 | 12 | 12 | 12 | 12 | 11 | 11 | 11 | 10 | 10 | 9 | 9 | 10 | 10 | 10 | 10 | 10 | 10 | 9 | 9 | 9 |
Wave (?)Graph  | ||||||||||||||||||||||||
 kJ (?) | 128 | 102 | 121 | 144 | 108 | 104 | 81 | 78 | 63 | 59 | 57 | 33 | 31 | 29 | 29 | 31 | 31 | 31 | 18 | 18 | 18 | 15 | 15 | 6 |
Wind (km/h) | ||||||||||||||||||||||||
| Wind State (?) onshore cross-onshore cross-shore cross-offshore offshore glassy | cross- on | cross- on | cross- on | cross- on | cross- on | on | on | cross- on | cross- on | on | on | on | on | on | cross- on | on | on | cross- on | cross- on | glass | glass | glass | glass | on |
High Tide / height (m) | 4:16PM 8.59 | 4:59AM 8.61 | 5:28PM 9.28 | 5:59AM 9.36 | 6:20PM 10.06 | 6:44AM 10.10 | ||||||||||||||||||
Low Tide / height (m) | 10:55PM 3.79 | 11:24AM 3.66 | 12:01AM 3.06 | 12:18PM 2.91 | 12:45AM 2.34 | 12:58PM 2.22 | ||||||||||||||||||
Wednesday 17 | Thursday 18 | Friday 19 | Saturday 20 | |||||||||||||||||||||
| Sunrise | - | - | - | - | - | 6:50 | - | - | - | - | - | - | - | 6:52 | - | - | - | - | - | - | - | 6:54 | - | - |
| Sunset | - | 7:23 | - | - | - | - | - | - | - | 7:22 | - | - | - | - | - | - | - | 7:19 | - | - | - | - | - | - |
 | |  |  | |  | |  | | |  | | | | |  | | | | | | | | | |
Rain (mm) | 1 | 1 | - | 1 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Temp. °C | 18 | 18 | 17 | 17 | 17 | 17 | 18 | 21 | 21 | 19 | 17 | 16 | 16 | 16 | 17 | 20 | 21 | 19 | 17 | 16 | 15 | 14 | 16 | 19 |
| Feels °C (?) | 14 | 15 | 15 | 15 | 16 | 15 | 15 | 19 | 19 | 18 | 16 | 15 | 16 | 15 | 17 | 19 | 19 | 19 | 17 | 16 | 15 | 14 | 16 | 18 |
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Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)- Wind Speed (km/h)
Recent Eyeball Surf Reports for Wales - South East
The wind is still cross-on at The Knap (moderate winds from the W at Cardiff-Wales Airport 4 km from The Knap). 0.9m 9s swell from the W with a 0.6m 11s groundswell, also from the W. 2 swells combining to make bigger set waves.
1 h 34 min ago
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