How to read the forecast for surfing using Windguru

Reading a surf forecast on Windguru can be overwhelming for beginners, but here's a simplified explanation to help you get started:

When you open Windguru, the initial step is selecting the spot you want to check. Simply type the name or location in the upper left corner under 'Search Spot' and make your selection. Once done, you'll notice multiple tables on the page as you scroll down, all seemingly indicating the same spot, days, and time but appearing differently. Here's a simple breakdown: Each table represents a distinct weather forecast model, relying on different data, accuracy, and time scales.

The first table isn't a forecast model but serves as an average summary of all forecast models for that specific surf spot and time. While you can trust this table for the next few days, keep in mind the information may not be absolute. While the ideal scenario involves comparing all forecast models, in day-to-day life, relying on the first table is generally sufficient.


Let's explore the specifics of the first table and clarify key terms. Pay close attention to the main indicators: wind speed, wind direction,  swell direction, wave height, and period.

1. Wind Speed

Look for the wind speed numbers, usually displayed in knots (1 knot = 1.852 km/h). The higher the number and the warmer the color (from blue, green, to yellow, orange, red, or purple), the stronger the wind will be.

2. Wind Direction

Pay attention to the direction the wind is coming from, described using compass directions (e.g., N for north, NE for northeast). This helps you understand how the wind will affect surf conditions at your spot. If you are confused by the arrow directions' significance, simply hover your mouse over the middle of the arrow, and you will see the letter designation for wind direction.

3. Wind Gusts

Refers to sudden and brief increases in wind speed that can occur in addition to the average or sustained wind speed. The higher the number and the warmer the color, the stronger the wind will be.

4. Wave Height

Indicates how big the waves are expected to be. It represents the average height of one-third of the larger waves in the area. Note that it doesn't mean all waves of this size will reach the shore.

5. Period

The wave period indicates the time interval between waves. A longer period generally means more organized and powerful waves. For example, 1m height waves with a period of 9 indicate small, smooth waves suitable for beginners and intermediate surfers. 1m height waves with a period of 12 or 13 mean powerful, strong waves for more advanced surfers.

6. Tide

Some Windguru forecasts include tidal information, such as high tide and low tide times. Understanding tides can help determine the best time to surf.

The crucial elements for interpreting the forecast include wind direction and strength, swell direction, wave height, and period. It's essential to emphasize that comprehending the forecast for any surf spot is futile without understanding the geographical position and nuances of the surf spot. Knowing how the spot responds to specific wind conditions and tides is key to making the forecast actionable.

Now, let's examine an example of the forecast for Carrapateira Beach and simplify its interpretation.


how to read forecast


Knowing that Carrapateira Beach faces the West and works better with a Northwest swell and Southeast wind, let's analyze the forecast for this specific surf spot day by day:


The low numbers and white color indicate very soft winds—almost none, creating perfect  "glassy" surfing conditions. On this day, wind direction doesn't significantly impact the conditions due to the lack of wind. The swell direction is West, offering favorable conditions with no wind interference. The wave height of 2m is good, with a period of 9, and the waves become larger and stronger with periods of 14 and 13. This day is suitable for experienced surfers, while beginners can enjoy good white waves.


Wind speed and gusts are increasing, and the wind direction is East-South-East, indicating a strong off-shore wind. The waves are growing larger with a substantial period, suggesting powerful waves. This day is suitable for experienced surfers who enjoy riding waves in strong off-shore wind conditions.


We can observe a change in the wind direction; currently, it is West-North-West and relatively light until 3 pm. After that, it becomes quite strong. Remember that the West wind, combined with the West swell, creates onshore wind that causes waves to close out.


Friday will have light wind, but the wind direction is North, known as 'Nortada' in Portugal. This wind on the West Coast tends to create messy, windy waves. Combined with 2m waves and a 10-second period, it can lead to quite challenging surfing conditions.


Despite the very light North wind,  we can see that starting from 11 am, the period becomes huge, and the waves reach 3 meters. This indicates truly giant and powerful waves. With almost no wind, the conditions are ideal for enthusiasts of really big and powerful waves.

The example of the forecast we were analyzing doesn't indicate conditions for beginners; it's more suitable for strong intermediate and advanced surfers. So, what are the best indicators in a surf forecast for beginners? Look for light wind or no wind, waves around 1 meter with a period of 8-10.

Hope this short, simple guide helps you read forecasts faster and interpret them correctly. However, it's essential to remember that you cannot fully understand the conditions solely by reading the forecast; you need to learn and understand how surf spots work. Even with a perfect forecast, you might arrive at the beach and find disappointment due to changes in ocean banks (for beach breaks), or waves not being as perfect as anticipated, or the forecast being inaccurate. Therefore, the most effective way to understand conditions is still to visit the beach and assess them on-site. Especially at the beginning of your surfing journey, learning from experienced surfers and taking surfing lessons with professionals is crucial not only for perfecting technique but also for gaining insights into how the ocean behaves.