What Does Swell Mean In Surfing? - Green Iguana Surf Camp

What Does Swell Mean In Surfing?

There aren’t many people who won’t know what surfing is, but for those who don’t, you basically jump on a board in the sea, and ride the waves back towards the beach.

That being an oversimplification, surfing has evolved loads over years and like most sports has developed a large following, it’s even one of the competitions in the Olympics and many people just participate for fun.

With surfing, unlike a lot of sports, it’s super dependent on certain conditions, like weather, tide, wind speed, wind duration and fetch.

With the sport depending on conditions of the sea so much there is going to be plenty of technical terms to do with surfing, and for those who don’t actually surf or perhaps live near a coastline then some of these terms and what they mean may be very alien to hear and you may lack an understanding of what they actually mean and how it affects surfing.

What Is Swell?

So, to put it in simple terms, swell is basically how the waves are forming and rolling in towards the beach. But really it defines the amount of energy that the wind is transferring to the sea. Swell can be identified by 3 different parts, height, period, and direction. 

The swell height is the measurement of the size of the swell at sea, it’s measured from the peak to the trough, the number of seconds from one peak, the historical data and the current data collected from the buoys out at sea.

The height of the wave actually refers to the average size of the waves, so not all of the waves will come in at the same size.  The height of the swell is typically measured in meters or feet.

Swell period, this is measured in seconds, this is because it measures the amount of time between one wave and the next. So if the wave period is longer, then this means that the swell has more energy and this usually means that it’s a better time to go surfing.

A rough guide to tell how good the swell is, is to see how long the swell period is, for example 1-5 seconds will mean there is no point in going surfing as the waves are the weakest they can be. 6-8 the waves are still going to be very weak and too close together to surf.

8-10 this is only marginally better, but it’s still going to be boring and difficult to surf these waves. 10-12 will mean you’re able to get some decent surfing in with some decent waves for an ok amount of time.

Finally, 13 seconds or more is considered great for surfing, you’re going to have a decent surf with big spaces between waves, and good timings. This will be generated by a big storm or super high winds somewhere out at sea.

Swell direction, on the swell report this will usually be shown with an arrow to indicate where the swell has traveled from using degrees based off of a compass.

The factors that affect swell direction will be incoming wind, which direction the beach is facing, how the seabed lies, and the general weather around the area.  

Different Kinds Of Swell

For surfers there is a distinct difference between wind swell and ground swell, this is the period between the two different swells. Really, they’re the same thing, hence both being called a swell, this is because they’re both created by the wind blowing above the sea.

Wind swell typically rolls in blocks of 10 seconds or less, but with ground swell this is usually between 10 and 20 seconds, this is usually caused by the stronger winds out at sea and the swell lasts much longer than a wind swell.  

There is also primary and secondary swell, these two different kinds of swell are separated by their period, height, and direction. Primary swell is the swell that is most likely to reach the coastline, hence primary.

The secondary swell is just the waves that don’t have quite as much energy and typically crash before they reach the coastline.

How To Read A Surf Report

Understanding what swell is, is all well and good, but now you’re going to be able to read a surf report. There are 6 main parts to a surf report and understanding them. Swell size, period, direction, wind direction, speed, and the tide.

Swell size, depending on your level you’ll either want small swell size if you’re a beginner and probably going to want larger waves if you’re more experienced.

Swell period, so as previously mentioned, 8 seconds is the minimum requirement to be able to surf waves.

Swell direction, understanding this combined with weather reports will help you to find where the biggest and best waves are for surfing.

Wind direction, this says which direction in degrees the wind is traveling from, typically you’ll want as little wind as possible when surfing. Offshore winds are best for those just wanting to surf, and onshore winds are for those who want to practice their tricks.

Wind strength, lower wind speeds are typically what to look for as these will cause less complications and the direction is less important with weaker winds.

Tide, learning the tide will help you to know when you’ll be able to surf at your favorite locations, learning a tide table is very easy to do.


So, we can conclude that the meaning of swell is the way waves are defined and if they’re able to surf or not. It typically categorizes waves as unable to surf, not too bad to surf on, and really good for surfing.

To find out if your location is good for surfing you can read surf reports to get a good idea on whether you’ll be able to go for a surf, but without understanding what swell is and what it means the surf report would be pretty useless for you.

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