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Swell period & how it affects waves
Swell period is the amount of time in seconds between 2 waves & is often categorized as short (< 10s), medium (10-14s), or long period (> 14s).
While this definition isnât all that helpful, knowing how it affects waves at your local break is.

Why? Because a 3 ft swell at 7s, 12s, & 18s will each produce a different sized wave with varying quality.
Shorter period swells (i.e. âwind swellsâ) produce shorter, peakier waves & have less energy, fewer waves to a set, shorter lulls between sets, & will produce smaller waves than a longer period swell of equal height.

Longer period swells (i.e. âgroundswellsâ) produce longer waves & have more energy, more waves to a set, longer lulls between sets, & will produce bigger waves than a shorter period swell of equal height.

Longer period swells are often preferred & result in a higher quality wave, but longer isnât necessarily better as it depends on what works best for your local break.
For example, point breaks are a great place for longer period swells as they allow the long lines to break evenly from left to right or right to left.
Contrary to a beach break where those long lines need to be âbroken upâ or ârefractedâ in some way with well-defined sandbars or another type of bathymetric (ocean floor) interruption, which is why some beach breaks can handle long periods & others leave you with nothing but closeouts.
A 3 ft swell at 7s, 12s, & 18s will each produce a different sized wave with varying quality.
The opposite is true for shorter period swells. At a point break, a shorter period swell wonât span the full length of the point & youâll end up with multiple sections not allowing the point to do its thing.
At a beach break though, thereâs a better chance of having nice, peaky waves with fewer closeouts & less need for solid sandbars.
These are just general guidelines though & every spot handles various swell periods differently, so whatâs considered the ideal period is relative to your local break (not to mention other variables).
đŹ Have you noticed what periods work best for you local break?
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