Seems like you have read our surf report post but want some more information on swell periods. Cool beans! After reading this article you’ll surely be the guy or girl to come to when looking for the perfect set of waves. It is actually quite simple to do.  

A powerful wave will be faster and have more push. This means you need less paddling and less volume on your surfboard. However, your timing has to be on point to catch a faster wave.

Each swell produces a set of waves on regular intervals. Swell period, or wave interval, measures the time between waves in a ’set’ of waves. The longer the time between sets, the more time the wave has to gain strength. In surfing, this equals to a more powerful wave. Long-period swells, or ground swells (over 12 second intervals), also travel faster and are usually not affected by local currents or winds. A short swell period of under 10 seconds is called a wind swell. 

The first waves of each wave sets are called forerunners. They carry a lot of water and are mostly used as an indicator on how strong the wave set is going to be.

A list of what kind of waves to expect with different swell periods

There are many ways how the conditions can change waves on the shore. Things like local winds, tides and currents can drastically affect what kind of waves you will be facing. However, the stronger the swell, the more likely you are of catching some rideable waves. Here’s a great rule-of-thumb to follow. 

Short swell periods (1 – 4s)

Short wave intervals create bumpy and inconsistent waves that are not best suited for surfing – even if the wind is in your favor. You’re better off waiting for a better swell.  

Medium swell periods (5 – 8s)

Short to medium wave intervals of 5 to 6 seconds pretty much follow the same rules as what we mentioned above. Local winds and swells might create surfable conditions in some cases, but don’t count on it.

Medium wave intervals of 7 to 9 seconds enhance the conditions tremendously. This definitely makes surfing worth trying. Our suggestion is to get out there early before everyone else.

Medium to long swell periods (9 – 12s)

Waves with a 9 to 12 second intervals are able to travel for some distances on open water. In the right conditions this can create good surf when the swells reach the mainland. Waves with these swell periods don’t retract, which means that they might not work for reef or point breaks. You will have a better time with longer intervals for these spots. However, for nice sandy beaches, you can definitely find good waves to surf with. Just make sure that all other conditions are in your favor as well. 

Long wave periods (13 – 15s)

Long wave interval swells are created by powerful storms far offshore. The bigger the storm, the more intense the wind will be. This, on the other hand creates larger swells. Most of the time the storms die out on the sea but their swells keep moving towards the mainland.

Long swell period waves are powerful enough to refract around sheltered coves creating great waves for a variety of spots. You may even experience hollow waves, or barrels, on both reef breaks as well as sand bars. This happens because the swell refracts as it hit shallow water and rises up. Long wave periods also create very consistent sets.

Long swell periods of 13s and upwards will surely bring out some high-quality waves for everyone to enjoy. You might as well call in sick and hope no one sees you.

Very long swell periods (over 16s)

If the intervals between waves are over 16 seconds, you are in for a treat. These waves carry an immense amount of water from the open ocean. As he swell hits shallow waters, the waves can refract around headlands and create powerful ridable waves. Most of the time these waves will be higher than the swell height.

So, keep a close eye on swell periods. The longest intervals will definitely provide some good times on the water.

Did you learn anything new about swell periods?

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