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How To Read a Surf Forecast

Originally posted on SURFER | By August Howell | Last updated Nov 26, 2024 3:47 PM ET

Surf forecasting is a science, but you don’t have to be a scientist to know when waves arrive. These days, numerous websites do most of the number crunching for you, and some give you all the raw data and information you’d ever need.

But how to make sense of all those numbers and colors? Knowing when to surf is half the battle, and in this guide, we’ll break down how to understand a surf forecast so you can get waves when the window opens.

What Is a Surf Report and a Surf Forecast?

A surf report is a snapshot of the current ocean and atmospheric conditions for a specific surf break at the time of observation. It provides information on wave size, intensity, wind conditions, and more, allowing surfers to determine the quality of the surf at a particular spot without having to physically be there.

Resources and Popular Surf Forecast Sites

Surfline: The most commonly used surf forecasting website today. Some sites focus on a specific region or wave, but Surfline’s network is vast and spans the globe. Its user interface makes it easy to check forecast models, buoy readings and the latest updates.
Stormsurf: Numbers-heavy and popular for long and short-term forecasts around the world, Stormsurf gives you all the data you can handle. Buoy readings, wave models, water temperature variations, it’s all there. The site is run by surfer Mark Sponsler, a self-taught surf meteorologist who’s been forecasting since 1985. Sponsler posts weekly videos breaking down high-level weather patterns and the minutia of changing seas.
Windy: Windy bills itself a mobile weather radar app with wind and waves forecast for kiters, surfers, paragliders, pilots, sailors and anyone else who spends time in the ocean. If you're serious about wind, there are not many better options better than Windy.
National Weather Service: The National Weather Service is a joint government-run program that tracks weather patterns across the country. It can also give regional reports and forecasts on swell, wind and tide. For surf breaks it’s not the only source one should rely on, but it’s great for a high-level view of conditions.

Key Factors in a Surf Report and Surf Forecast

These are the biggest factors to know when looking at a surf report/forecast: wind, tide, wave size, period and direction. The goal is to learn which elements work in harmony at a given wave. Some places come alive on a long period swell with high tide and southerly winds, but those same factors might flatten another spot. Learning which wave likes what conditions takes time and effort. Surfers spend years studying a wave’s nuances. Talk to fellow surfers or professional meteorologists to better understand a region's tendencies.

Check the Buoys

Buoys are a surfer’s best friend. They are one of the more common and useful tools for professional and amateur forecasters alike. Thousands of buoys worldwide are maintained by federal, state and scientific agencies and record important data for surf forecasting, including winds, temperature, wave size, period and direction. Weather forecasters have satellites; surfers have buoys. Click here to see the National Oceanic and Atmospheric Administration's Database to find a buoy near you.

Wave Size, Period and Direction

A little self-explanatory, these three above factors determine how big the waves coming to shore will be. Size refers to the average wave size within a swell, measured by offshore buoys. Each swell comes from a specific direction measured in degrees on the compass. The shape and angle of the coastline determine which swell direction is ideal. For example, a north-facing beach will be exposed to swell coming down from the north. An east-facing beach is more likely to see waves when they come from the west.

The wave period is the gap between wave peaks, measured in seconds. The longer the period, the larger the waves will be. Long-period swells, typically 15 seconds or more, have more energy. Short-period swells, 14 seconds or less, tend to send more choppy and less organized waves. For example, a 3-foot, 10-second interval swell can produce waves around 3-4 feet. But a 3-foot, 20-second swell can be double that height.

Wind

Like the wave direction, the angle of the coastline, beach or reef determines which wind is best for the waves. Waves generally have their best conditions in offshore wind, when it blows from land to sea. The opposite, onshore wind, blows from sea to land and usually results in choppy, messy waves. For the cleaner conditions, you’ll want a wind that comes directly opposite from the wave’s direction For a beach that faces west (and takes a west swell), an easterly wind will result in groomed, offshore conditions. A north-facing coast will like south gust, and waves exposed to the south will be groomed by northerlies. Be sure to check the wind strength as well in your forecasting, as too much wind can make for a difficult session.

Tide

The depth of water has a major effect on any given surf spot. Tides have two lows and two highs every 24 hours. Like the wind, a favorable tide varies depending on location. Some waves prefer lots of water, others prefer a negative (low tide). At higher latitudes in Northern Europe or North America, six or seven-foot tide swings are not uncommon. Most reef breaks, particularly in the tropics, are hypersensitive to tide changes. One foot can be the difference between hollow tubes and dry closeouts. Tides can be predicted years in advance, so refer to tide charts on forecasts to see the high and low points on a given day.

Seasonal Swells

Seasons also play a big role in when waves break. For example, Mavericks, the big wave in Northern California, will never break in the summer because there are no swells generated in the Pacific Ocean big enough to do so in those months. Mavericks requires long-period west/northwest swell from low-pressure systems in the northern Pacific, which usually form between October through March.

However, summer in the Northern Hemisphere is a great time for surfing south of the equator. A more active South Pacific Ocean in April through September means prime time in Indonesia, Mexico, South America and South Africa.

How To Interpret Surf Report Data

Now that you’re familiar with the key terms and factors, it’s time to learn how to interpret surf report data. Here’s a step-by-step guide to understanding a surf report:

Check the wave height: Determine if the wave size is suitable for your skill level and preferences.
Review the swell period: Look for longer swell periods (10+ seconds) for better-quality waves.
Assess the swell direction: Determine if the swell direction is optimal for your surf spot, taking into account the orientation of the coastline.
Evaluate the wind direction and speed: Look for offshore winds with low speeds (below 7 mph) for the best surf conditions.
Consider the tide: Understand how high and low tides affect your specific surf spot and plan your session accordingly.

Accuracy

Keep in mind that even the most scrutinized surf forecasts are not 100% accurate. While the technology improves by the year and forecasters do the best they can, Mother Nature loves to throw curveballs. Learning and consistently studying the factors above and how they help or hinder the waves in tandem is essential to finding the best waves possible. Whether you’re surfing around home or on a strike mission to somewhere remote, a good report can be the difference between scoring and skunked. But even so, there’s only one surefire way to know what the waves are doing—get eyes on it.

This article first appeared on SURFER and was syndicated with permission.

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