surf forecast - how to read and understand it

You are taking a surf holiday and want to know how the wave and surf forecast looks like for the next few days? You want to know, how high the waves will be and wether the wind is going to be onshore or offshore? You decide to open a surf forecast website or app but don’t understand a thing? Then let us help you: here comes the instruction on how to read the surf forecast!

How to read a surf forecast – Table of Contents

surf forecast richtig lesen

Interpretation of the surf forecast – an art in itself

A surf forecast makes life much easier for many surfers around the world. Thanks to these predictive forecasts, you can at least roughly estimate whether it’s worth getting up early to check the waves or whether it’s better to sleep in. Although wave forecasts are never 100 % accurate, they do provide clear indications as to whether the ocean will produce decent waves in the coming week. However, the interpretation can sometimes be a little more complicated, as the forecast contains numerous factors that significantly influence the surfing conditions.

surf forecast online

Which surf forecast are there?

There are many websites and apps for the forecast of waves. These include surf-forecast, surfline, windguru and many more. These pages offer a wealth of information, some of which is hidden and requires a certain amount of interpretation. That is why it is not always easy, to understand a surf forecast correctly. Here we summarise what information surfers can draw from the forecast and where they can find it.
surf forecast el cotillo

What factors are important for a surf forecast?

  • Period of the swells
  • Swell direction
  • Wave size or height
  • Wind strenght / speed
  • Wind direction
  • Secondray and tertiary swell
  • Tides
  • Rating in Stars
  • Wave energy
surfcamp fuerteventura oktober surfspot

Basic knowledge of the surf spot is essential

To understand and interpret a surf forecast correctly it is extremly important to know the surf spot and the local conditions. These information include the best tide for the spot as well as the geographical orientation. Using these parameters, you can deduce from which direction the swell should come so that the waves hit the coast in the best possible way. At the same time, this knowledge also allows you to determine the wind direction required to create offshore conditions.

surf forecast website

Read the Surf Forecast on

If you need the surf forecast for Europe, Surf-Forecast is a great website. You can easily understand the forecast by looking at the different parameters step by step. Let’s go: Go to and search for the beach you’re interested in. For example, let’s take a look at El Cotillo beach.
website surf forecast

Swell direction, swell size and period

Which factors are most important for a surf forecast? Swell direction and size as well as the period have a decisive influence on wave quality. This means that these three factors play a decisive role when reading and interpreting the wave forecast for a particular spot.
surf forecast swellrichtung

Swell direction

The swell direction indicates the direction from which the swell hits the surf spot. It is important that it matches the direction of the spot so that waves arrive.

Otherwise the waves can be significantly smaller or even completely flat. Note: Move the cursor over the arrow to find out the exact swell angle.

surf forecast swellgroesse

Swell size and wave size

The swell size indicates how strong the storm was on the open sea, which influences the formation of the swell. The stronger the storm, the bigger the swell and the waves that hit land. However, it is important to note that the swell size does not necessarily correspond to the actual wave size at the surf spot. This also depends on other factors such as the direction of the swell, the sandbanks and the tide.

surf forecast swellgroesse

The wave size is given in metres or feet (1 ft ≈ 30 cm) and is calculated by the surf forecasts using various parameters such as the period, swell size and direction. This is merely an estimate and not an exact figure. However, especially with a longer period, it can be assumed that the waves will be larger than the wave size specified in the forecast.


Swell period

The swell period is given in seconds and indicates the time it takes for successive waves to pass the same point. The longer the period, the more organised the waves are and the larger they become.

It is also often possible for different swells to hit the coast at the same time. The primary swell is then listed as shown in the screenshots below, followed by other (secondary) swells. If a secondary or tertiary swell is travelling, this means that a second or third low pressure area has formed somewhere at sea, which is also sending waves to the spot.

surf forecast wellenenergie

Wave energy in the surf forecast 

A stylised wave is used to indicate the energy content of the wave. Although the energy in kJ doesn’t mean much to most surfers, it is a good way of roughly estimating whether the swell will work on a particular beach.

Waves from 100 kJ are often just surfable. A range of 200 to 2000 kJ roughly covers the good wave sizes. From 1000 kJ to 5000 kJ it becomes challenging, and only a few spots still work at all.

Wind strength and wind direction in a surf forecast 

surf forecast wind

The wind also has a significant influence on the quality of the waves. No wind or offshore winds (offshore) are the ideal conditions for any surfer. The wind strength is given in km/h, while the arrows indicate the wind direction. The colour indicates whether the wind is coming from a favourable (offshore) or unfavourable (onshore) direction. To determine which wind direction is ideal for a particular spot, it is important to know how the spot is orientated.

surf forecast bewertung

Rating of the surf forecasts

Many wave forecasts also offer a rating of the conditions. At, this is represented by the star rating, with 10 yellow stars being the best rating and not a single star being the worst. However, these ratings are calculated automatically and are therefore not always meaningful.

surf forecast gezeiten


It is also important to know how high the water is, whether it is rising or falling and what the tide is like in order to predict the wave quality. This is what surf forecast shows you.

Once you have received all the basic information and know what data a surf forecast provides and how to interpret it, it depends on how well you can memorise these points and how often you deal with the surf forecasts.

In another blog post, we will introduce you to the portals and Windguru.

We wish you always good waves!