On the east coast, many of our standard beach breaks do not handle the longer period swells very well. In Delmarva, my home, the medium period swells are generally best (9 - 12 seconds). Anything longer than that, tends to close out.
Reef breaks tend to be much better with the longer period swells. This is because with the sand bottom breaks, the sandbars are always moving around and generally much more dynamic. Reefs on the other hand, are static (not moving).
Alright... I think it needs to be explained again, i think some people are not understanding... A swell period is the amount of time it takes 2 CONSECUTIVE CRESTS... To pass over the same point.
Picture a Pole in the water... A piling or something of the sort. The Swell period would be the time between when one wave hits the piling, and when the wave behind it hits the piling.
It is not the "Time Between Sets," But the time between each wave in a set.
Also a longer period swell will produce a longer wave face, making them great for point breaks. A short period swell tends to be more peaky and 'disorganized' if you will, making them better suited for beach breaks.
That being said, here on the east coast we are usually surfing between 7 and 12 second swell periods, and usually on beachbreaks, So the difference between swell periods is usually hardly noticeable. However if you go somewhere with lots swell periods and lots of different setups (points, reefs, beachies), the difference between swell periods and their 'surfability' will become as clear as day.
my break faces east,is exposed,is a series of little sandbar beachbreaks,so we need a shorter period peaky swell,which usually means a windswell,plus the right tide and the right sandbar for the angle.that's why we get good waves in the Summer when most other spots are flat.
i feel like this tuesday when i go surfing gd willing. That if i sit in the line up, and i count how much time goes by when one wave passes in front up me during a set, then wait for another to pass me if in the same set. I feel that each set has a different timeing, and a little off from the forcast.