How to read surf forecast like a pro surfer

Choose where to surf by yourself!

Contents

Planning a surfing session

To see if you can have a safe and a productive surf session in a specific spot on a specific date, check this:

  • Swell direction
  • Swell height and period
  • Tide (low/medium/high)
  • Wind (direction & speed)
  • Working wind and swell for this specific spot
  • Type of break: beach break, point break, reef or river mouth
  • Tips from locals

Waves are more than just swell!

A wave is formed by:

  1. Swell
  2. Tide
  3. Wind
  4. Type of break

The break doesn't change, it just depends on the spot, but other parameters can be forecasted or calculated.

When all factors are present, a so-called groundswell forms. That's a row of waves with a certain height and period, which appears after storm in the ocean. It often brings clean, well formed surf.

Windswell

Wind forecast map

When there’s no swell, so called windswell is formed. It’s typical for bays and gulfs.

It's created by less powerful wind and storms that occur closer to the shore. In this case, waves don’t have enough distance to form clean patterns, so the surf is often broken up.

For educational purposes, let’s learn to read a surf forecast for a spot that has swell, tides and wind.

Reading swell forecast: direction

Wind forecast map

1. Swell direction shows you where the swell is coming FROM

2. Some spots are very sensitive to swell direction, for example:

  • located in a bay: if the direction is not right, the waves simply won't reach the shore.
  • the shape of the seabed could be such that if the swell comes from on the right, then the waves will be long and even, but if it is on the left, then the surf length will be short.

3. The majority of spots are not that sensitive to small variations, and many generally work in all directions of the swell.

Reading swell forecast: height and period (1)

Let’s say, the swell direction is good for this spot.
It's time to determine wave size.

It’s based on:

  • swell height (measured in meters/ft)
  • wave period (measured in seconds)

The general rule is: The higher the swell, the more powerful the waves will be. Wave period (the time of the complete wave cycle) will determine the size of the waves.

Reading swell forecast: height and period (2)

To roughly estimate actual wave height, use this rule:

Swell period Wave height
< 11 s wave height < swell height
11-12 s wave height = swell height
14-19 s wave height > swell height
> 20s wave height = 2 x swell height

Example:

If the swell is 1.7 meters high, and the period is 12 seconds, the wave will probably be approximately 1.7 meters or a little more.

Wind for surfers (1)

Best wind = no wind! (glassy conditions)

If there’s wind, look at speed and direction

Wind direction Influence on waves
Offshore good wall of the wave
Onshore more quickly closing out
Crossshore possible current

Wind for surfers (2)

OFFSHORE

Wind is coming from the land, pushing against the face of the wave, creating neat and tidy conditions. The offshore wind helps waves get a clear shape. It’s similar to “no wind” conditions.

CROSSSHORE

Wind is coming from the sides of the break. Depending on the strength of the wind and the type of break, the wave can be still surfable, however it’s shape tends to get messed up. It can create or affect the current.

ONSHORE

Wind is coming from the ocean. It is the worst type of wind, since the wind is pushing the wave from the back and messing it up. If the wind is light, the wave can still be surfable.

Tides for surfers

Determine the best time of day to ride!

  1. Most surf spots are sensitive to changes in water levels. See spot info for the working tide level. Even if a spot works on all tides, the quality of waves can change with the water level.
  2. Tides don't need to be predicted, they are determined by the moon and the sun and can be calculated.
  3. General rule: waves on a low tide are sharper than on a high tide
  4. Depending on tides, the currents on a spot can change.

How to choose a spot: when the spot is working

Check out the SPOT INFO section or other resources to learn about a certain spot.

Crucial parameters are:

  1. Working swell directions
  2. Type of break
  3. Working tides
  4. Working wind directions

How to choose a spot: types of break (1)

On point breaks:

The waves rise due to the part of the land that protrudes into the ocean. It can be an island, a small peninsula, a cape, a ridge of stones.

On reef break:

Waves rise up colliding with the reef or coral shelf. Due to the fact that the reef remains unchanged, waves like that have more constant shape and size.

On beach break:

Wave are formed due to the alluvium of the sandy bottom which generate “sand banks”. Unfortunately, beach breaks have much more instability and mobility than point and reef waves, as the shape, length and peak of the wave is constantly changing.

How to choose a spot: types of break (2)

Sometimes you can also check the type of break using the sattelite map view.

How to choose a spot: reviews from locals

Why are they worth reading:

  1. They come from people with first-hand knowledge of the spot.
  2. There could be local tips like optimal swell energy for this spot or wetsuit thickness recommendation.
  3. There could be information on the current situation on the spot (restrictions, trash on the shore and etc.).

Thousands of surf spots have reviews from other surfers in Windy.app.

Bonus: how to forecast the swell (as big wave surfers do)

The strongest storms are associated with cyclones (low pressure areas, the center is marked by the letter “L” ). Winds blow along isobars (lines around the letter “L”). The closer the isobars are to each other, the stronger the winds.

These storms produce swell.

If you know where the cyclone is, you can predict where the swell will be in advance.

Bonus: swell propagation on the map

T+00h

T+12h

T+24h

T+36h

Recap

Always check:

  1. Spot working conditions
  2. Swell direction
  3. Swell height and period
  4. Wind speed and direction
  5. Tides

-> Go surfing :)

Now you know how to check the surf forecast by yourself. Good luck!


Reviews
24

G
Guest
10 April 2023
Very informative
G
Guest
09 January 2023
Hello! I'm from Windy.app. Swell forecast is back! There's been an issue on our provider's side, but now it's all fixed and fresh 10-day swells forecast is again available for spots and on the map. If you still want a refund or if you ever have any questions - don't hesitate to contact our user support at [email protected]!
G
Guest
05 January 2023
The biggest swell in years for the California coast and every spot has had the swell hight and period removed? Unavailable? Not even there anymore. I want my money back. What a complete waste.
G
Guest
28 December 2022
Typo in big wave bonus...assosiated is spelled incorrectly. It's associated.
G
Guest
03 November 2022
Hey guys! We have fixed the download button Please check it out btw contact me [email protected] I work for Windy.app
G
Guest
02 November 2022
Great guide, thanks a lot! Just the Pdf download doesn’t work(at least for me)
G
Guest
02 November 2022
Great!!
G
Guest
02 November 2022
Spanish please
G
Guest
02 November 2022
Top guide????
G
Guest
02 November 2022
Super! Thanks!
G
Guest
01 November 2022
Top!
G
Guest
30 October 2022
So necessary! Thx
G
Guest
29 October 2022
Thank you for the guide!
G
Guest
28 October 2022
Muito legal esse guia !
G
Guest
28 October 2022
Top!
G
Guest
28 October 2022
Enjoyed this article
G
Guest
28 October 2022
Such a good app!!! And this piece about forecasts is just great for beginners + good reminder for us all
G
Guest
27 October 2022
Great app for weather forecawt
G
Guest
27 October 2022
Epic
G
Guest
26 October 2022
Excellent summary! Thanks for the wonderful app!
G
Guest
25 October 2022
Your swell energy feature is awesome! more accurate
G
Guest
25 October 2022
Its a really good teaching material! Thx!
G
Guest
25 October 2022
Thanks guys for an amazing product! Keep up the good work! P.s. Please add swell alerts, that would be more than useful!
G
Guest
25 October 2022
Nice guide!