How To Read Surf Reports & Understand Surf Forecasting Websites
If you have ever wondered:
Where surf forecasting websites get their data from?
What is wave period?
how do you read a surf report?
Then this guide is for you.
In our guide to learning how to read a surf report for beginners we take a look at each of the ingredients that go into the making of a surf forecast and teach you how to read a surf report effectively.
THE COCONUT WIRELESS
In the days before the internet, savvy entrepreneurial local surfers were known to set up premium rate phone lines and provide eye ball surf checks for land locked hopefuls.
A far cry from the good old days and the coconut wireless, todays surf forecasting websites take a huge amount of data and compile it into easy to read formats.
Surf forecasting websites have pulled surfing into the 21st century.
LEARNING HOW TO READ SURF FORECASTS
Surf forecasting is seen by some as somewhat of a dark art. With many taking a dim view the moment the surfing conditions on the beach don’t match the pre conceived readings online.
For new or developing surfers understanding and deciphering all the information provided can be a mine field, leading to misjudged surf conditions, disappointed expectations and a distain for ‘trusting’ surf forecasting websites.
Taking the time to learn and understand the basics of how to read a surf forecast is a good skill to learn and will help you to put together another piece of the surfing puzzle.
WHAT IS SURF FORECASTING?
Surf forecasting is a collection of meteorological data combined with complex algorithms and swell models to predict local surf conditions in advance.
All designed to assist surfers in understanding what surf conditions can be expected at their local surf spot, displayed in a way that is easily digestible and quick to understand.
WHAT IS SWELL?
Swell is energy that has been transferred into the sea by wind. The longer and stronger the wind blows (like a hurricane) the more energy that is transferred and so larger the swell.
This energy then propagates from where it is created out into the ocean, much like ripples in a pond.
WHY IS SURF FORECASTING USEFUL?
As any surfer will tell you - having advanced information at your fingertips can play a big role in the planning of surf opportunities and allows the modern surfer to manage their time efficiently. With surfing conditions in constant change from one day to the next, the insights provided through surf forecasting proves invaluable to the surfer whose days in the water are limited.
On a national or international level surf forecasting provides data backed guidance with the planning of successful surfing events and competitions. Large scale surfing competitions are big business with events becoming increasingly popular. Well known non surfing brands provide considerable sponsorship deals in exchange for exposure to the ever growing surfing audience. Surf contest directors are under more pressure now than ever to hold surfing contests that allow surfers and destinations to showcase their potential.
On a philosophical level, surf forecasting provides the average every day surfer with the means for a higher understanding of their local surf spot, surfers now have the means to learn and understand the favoured weather patterns or swell period and direction needed for that elusive secret spot. This deeper understanding brings with it a further appreciation for the waves we ride and the elements needed for surfing to be enjoyed to it's fullest.
WHERE DO SURF FORECASTING SITES GET THEIR DATA FROM?
All surf forecasting websites glean at least some of their data from the same source. This data is provided by the American agency National Oceanic and Atmospheric Administration. (NOAA)
This is a US government funded service and provides the data for free, allowing surf forecasting websites to collate what data they wish and display it in a format that is useful for surfers.
Using complex algorithms, mathematics and historical data, these individually unique swell models decipher the information and produce the forecasts we see online.
LEARN THE BASICS OF HOW TO READ A SURF REPORT
There are a whole host of surf forecasting websites to choose from, a great place to start is to find a surf forecasting site that suits you, your location and the depth of knowledge you wish to gain form it.
Take look through the list below and find a site you feel comfortable with, you should find the layout of the information easy read, even if you don’t quite understand it all yet. How each website displays it’s data is key to the user understanding what the surf report actually means.
List of surf forecasting websites:
HOW TO READ A SURF REPORT FOR BEGINNERS
KEEP IT SIMPLE
Only concentrate on the three main areas which will provide you with the most valuable and important snippets of information. These bits of information only become valuable to you when you can relate what you see on the screen to what you see on the beach.
Once you understand these three basics you can start digging deeper, which we cover later in this article.
Wave height (not swell height)
Wind direction & strength
1) WAVE HEIGHT
Not to be confused with swell height. Wave height represents the average size of the waves you may expect to see at the beach.
Wave height is typically measured in feet although most forecasting sites will allow you to switch between feet and meters.
In a separate guide we discuss referring wave height to body parts for easier and often more accurate wave height assessment.
2) WIND DIRECTION
Wind direction is shown by an arrow icon. The direction of the arrow represents the direction the wind has travelled from. (direction the wind is originating from)
Learning the difference between what a favorable wind direction is and what isn't, plays a massive role in the quality of the surf.
Wind strength can be just as important as wind direction. Each surf spot will handle various wind strengths differently. Some areas may be better suited to strong off-shores, others may be protected or sheltered at certain stages of the tide. Generally speaking most surfers will prefer little or no wind.
The important point to remember is you need to relate what you see on the beach to what the forecast predicted.
3) TIDAL MOVEMENT
For each 24 hour period there are two high tides and two low tides. Understanding which tidal state suits the beach best or favours the shape of waves you like to ride should be a factor in where and when you surf.
Some surfers may prefer waves, which are steeper, faster and break quicker. For surfing in Newquay, these surfers will often wait for the lower stages of the tide for these waves.
If you can remember surf sessions where you found the waves hard to catch, too fat and lumpy or the waves were not pealing that well, the tide may be an influence in this and knowing what tides suit the beach best should affect your decision of when and where you surf.
Learn which state of the tide suits your beach and your surfing the best. Being aware of the tides, how they work and affect the waves is important to your surfing decisions.
Understanding these three basics when reading a surf report and relating your online understanding to what you see on the beach is key to managing your expectations and to really getting to grips with reading a surf report accurately.
SURF FORECASTING TERMINOLOGY & FURTHER UNDERSTANDING
Once you have mastered the basics it’s time to dig a little deeper and begin to relate some of the more in-depth topics into your surf forecasting understanding.
PRIMARY / SECONDARY SWELL
WHAT IS WAVE PERIOD?
Wave period is measured in seconds and is the gap between one wave and the next. Simply said the wave period is the amount in seconds that pass between each wave.
The higher the wave period, the more energy in the swell and so the larger the wave and more often than not this results in better quality waves for surfing.
Wave period can be measured from trough to trough or from the crest of one wave to the next.
Ground swell” refers to a swell that has a wave period of roughly 12 seconds or higher.
Wind swell" refers to a swell that typically has a wave period between 1-11 seconds.
A ROUGH GUIDE TO WAVE PERIOD & QUALITY
Wave period is measured in the seconds between each wave.
- 1-5 Un surf’ble - Created by local weather conditions and usually accompanied with bad on-shore winds which created the minimal swell. Such a low wave period will mean small mushy, weak waves breaking very close together.
- 6-8 Weak - Only a slight improvement from a 1-5 second wave period. Expect waves to be very close together, barely rideable, weak and mushy.
- 8-10 Poor to Average - Waves with this period are beginning to show slight signs of quality. Expect crumbly, fairly weak waves with minimal wave face. Waves will break close together but will be surf'ble.
- 10-12 Good to Great - Decent surfing waves arriving in uniformed sets. Expect more wave face, longer rides with more pronounced shape.
- 13+ Excellent - Great long period ground swell generated by a large storm and high winds far out to sea. Local wind conditions permitting expect uniform lines, big gaps between sets and good times.
WHY ARE WAVES BIGGER WHEN THE WAVE PERIOD IS HIGHER?
Waves are generated by strong winds blowing across the open ocean.
The harder and longer these winds blow, the more energy that is transferred from the wind in the form of kinetic energy, resulting in longer wave periods within a swell.
Large swells with long periods travel extensive distances across open ocean, their energy extending from the oceans surface towards the sea floor, otherwise termed “ground swell”.
When this ground swell reaches a shoreline it is forced upwards by the sea floor into a wave. (shoaling) The longer the period the more energy that is underwater and that can be forced upwards forming a larger wave.
As the wave period increases the more uniformed and orderly the waves will look as they roll into the beach.
WHAT IS WIND SWELL?
A wind swell is created by local weather conditions a few hundred miles off a coastline. The wave period is short because the winds creating the swell do not blow strong enough for long enough, having transferred only a small amount of energy into the sea and typically a short distance to travel before reaching coastlines.
Unlike long period waves that travel unopposed over vast distances deep within the ocean, wind swell travels within a few meters of the oceans surface and is affected by opposing winds and existing sea states.
WHAT IS SWELL DIRECTION?
Typically swell direction is shown as an arrow icon. Much the same in how wind direction is shown, the arrow shows the direction the swell has travelled from.
Typically coastlines will receive incoming swells from one or two predominant directions. In the same way as regional areas receive prevailing winds from a particular direction due to it's geographical location and weather systems.
Surf breaks act in much the same way and will have a favored and predominant swell direction.
The direction that a beach faces, the topography of the seabed and the angle the incoming swell reaches these features will have a huge affect on how waves form and break.
WHAT IS THE DIFFERENCE BETWEEN A PRIMARY & SECONDARY SWELL?
With oceans being so vast and so easily affected by varying winds, multiple swells are formed within relatively small areas, resulting in multiple swells travelling towards or reaching coastlines within the same period of time.
In this scenario the different swells are categorised according to their wave period, direction and swell height. The swell with the most potential to reach the coastline is usually given the title of ‘primary swell’, subsequent swells then will be of a lower period and categorised as secondary swells.
A factor in deciding which swell is the ‘primary swell’ is the anticipated wave height a particular swell will be produce when reaching the beach.
WHAT IS THE DIFFERENCE BETWEEN SWELL HEIGHT AND WAVE HEIGHT?
Swell height refers to the average size of the swell out at sea. This is measured from the peak to the trough and the seconds between one peak and the next using historical and real time data gathered from off shore buoys.
Wave height is the average wave size a surfer may expect to see when reaching the beach.
Depending on the swell model used by differing surf forecasting websites each may show a slight difference in wave height.
HOW FAST DO WAVES TRAVEL?
Swells and the individual waves within a swell travel at different speeds. For the swell to keep moving forward, individual waves are constantly rotating positions. Fast waves catch up with slower waves & slower waves are caught up by faster waves in a continuous conveyor belt.
Swell speed is measured in nautical miles per hour or knots. (1 knot is 1.2 miles on land.)
In order to work out the speed that a swell is travelling multiply the wave period by 1.5. The result is the speed the swell is travelling in knots.
To work out how fast individual waves are travelling multiply the wave period by 3.
WHAT IS WAVE DECAY?
Wave decay refers to the energy loss within a swell as waves propagate outwards from where they were generated. The further the distance travelled the more energy is lost and is dissipated.
A quote from Willie Wong’s blog ‘Bubbles Bad, ripples Good’ he states
“dispersion is the tendency for the wave to occupy more and more area as it propagates.”
HOW ACCURATE ARE SURF FORECASTING WEBSITES?
Surf forecasting websites have become very accurate over the past 10 years. The introduction of near shore swell models, the ease of gathering meteorological information and the freedom of data provided by NOAA has allowed surf forecasting sites to provide detailed relative information for surfers. Combined and developed with local impressions surf forecasting websites are at the forefront of surfing.
However the caveat remains that understanding and interpreting the data provided is a personal expectation that needs managing.
WHAT IS SHOALING?
Shoaling is the name given to how a wave forms and breaks.
As waves reach the shallow water of the coastline the wave runs out of space. Think of the wave as a recirculating sphere that rotates towards the shore, as the sea bed becomes gradually steeper and the depth of water decreases more of the waves energy is forced upwards towards the surface, gradually increasing the waves height.
Waves with a longer period have more energy and so more water is forced upwards creating a larger wave.
3ft @ 10seconds = 2-3ft wave with not much power
3ft wave @ 16 seconds = a much larger and more powerful 4-5ft wave
Waves will start to break in water 1/3rd the height of the wave. 3ft wave will break in 5ft of water. The topography of the seabed will affect how quickly a wave will form and how it will be break.
Waves that travel from the deep ocean and reach a sharp incline will form quickly and break fast.
Waves that travel on a gentle incline will form slowly and crumble.
WHAT ARE WAVE BUOYS, HOW DO THEY WORK?
Wave buoys give surf forecasters a real time idea of what is happening out at sea. Contrary to common beliefs wave buoys do not provide much information for day to day surf reports.
The majority of the data needed for surf forecasting comes from a variety of meteorological weather stations, satellites and historical data, enabling a forecast or advanced picture of what can be expected to be produced.