The tide (the daily toing and froing of the sea around the world) has a strong effect on wave quality and size at Porth Neigwl. We generally have 2 high tides a day here in North Wales which are seperated by about 12 1/2 hours.
We tend to experience taller but shorter period (closer together) waves on the dropping tide. This can help in smaller swells but can be detrimental in larger conditions when it creates a lot of water movement and rips. This is why you may often see the comment regarding an increase in the surf on the dropping tide in our surf report.
Low tide, and the first few hours during the filling tide, moderates the swell and we tend to see the period lengthen also. This makes the waves become more organised and possibly better for beginners. We have a steep high tide sand bar at the moment which can create heavy shorebreak waves which are no real use to anyone. For more advice about current beach conditions check with west Coast Surf Shop - we are always happy to share some knowledge (we may even stare into the middle distance and talk about the great swell of '97.)
How We Measure Surf Height
Reporting the height of the waves is very subjective and we use terms such as waist high, chest high, head high etc. This is based on the height of the wave if you were surfing on it (not standing in the water!!!). It is to provide an approximate guide to the surf size, but as the surf is constantly changing from minute to minute, the actual conditions could be different from the report.