How to read a surf forecast

How to read a surf forecast

Being passionate sportsmen, we at WINDY.APP are on a mission to provide our users with the most accurate and reliable surf forecast as possible. We are combining weather reports from over 30 000 weather stations across the world to help you to understand better where and when to surf next.


First off – let’s cover the basics. Think of this as your Bachelor in Understanding The Surf Forecast degree. For your degree, these four variables are the basics: swell, swell height, swell period and swell direction. Understand this holy foursome and you will have a decent package of know-how and you are ready to start planning your next surf session. 

If you want to dive deeper and earn your Master degree, you should aim to understand the following: wind direction such as onshore wind, offshore wind, wind gust, and tides.

Swell is a collection of waves generated by specific conditions like a storm. Swell can travel a long way to the beach (think like 2000 miles offshore). The swell height, period, direction are the ones that determine how surfable is the swell. 

Swell Height
Swell height is measured from the base of the wave to the top of the wave. Note: swell height does not always mean the height of the wave as it is an estimated average height of the highest one-third of the swells. Gives you a picture of an average height of the possible waves. 

Swell Period
An extremely crucial part of surf forecast – also known as a swell frequency. Measured often from one peak to another peak. Correlates in how much energy there is in a swell. A thumb rule: the longer the period the more energy in waves. 

Swell Direction
The direction from which the swell is coming. A thumb rule: the more directed the swell is when hitting your local beach the stronger the waves. Look for islands that might block the incoming swell. With WINDY.APP’s animated arrow you can check hour by hour how the swell direction changes. 

Swell energy
Indicates the power of the predicted waves and can be the most useful guide to how powerful the surf is likely to be. It is a combination of both wave size and period.

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Wind Direction - Onshore wind 
Blows from the sea towards the beach and it’s usually not the best for surfing as it creates choppy and smaller, mixed waves and makes them break earlier. 

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Wind Direction - Offshore wind
Moderate offshore wind is often associated with the best time to surf. Offshore wind slows up wave breaking and steeper and clean face when it breaks (good for beginners!).

Wind Gust
Gust is a sudden increase in the wind's speed that lasts no more than 20 seconds. With strong wind gust, it can change the surfing conditions rapidly. A good thump rule: 9mph gusting to 18mph will make surfing conditions messy. 

This really depends on the spot and you should always ask the locals about the best timing to get out in the water. Most often it’s when the tide is moving either “low going high” or the tide is on the rise.

Final remarks - extra curriculum 

The modern weather forecast is scientifically as accurate as possible but as anyone who has been in the water and witnessed the ever-changing nature of Mother Nature (sometimes you can go in an hour from great surf into abysmal) – make sure you have this covered:

+ Don't forget to select SURF setting from the WINDY.APP selection to get the essential information for surf forecast.
+ See if there are live stream cameras available at the spot - check the current forecast and see how it looks like in reality.
+ Ask the locals in the WINDY.APP chat how are the surfing conditions.
+ Don't forget to see historical data (available as a PRO feature) - this I essential if you are planning a surf trip for a specific time.

In the end, with surf forecast the same thing applies as with surfing itself – the more time you spend at your local surf spot, the better you become.