Understanding a surf forecast is one of the most valuable skills a surfer can have. It’s the difference between paddling out to perfect peelers—or showing up to flat water and frustration. The best surfers don’t just rely on luck—they know how to read the ocean’s signals through data.
Here’s how to decode surf forecasts like a pro and time your sessions for the best waves possible.
1. Swell Size: The Height of the Energy
Swell size tells you how big the waves are likely to be, usually measured in feet or meters. But there’s a catch—it doesn’t always equal the actual wave height you’ll surf.
That’s because swell size measures open-ocean waves before they hit the coast. Local factors like wind, tide, and seafloor shape (bathymetry) can make the waves bigger or smaller by the time they reach the lineup.
Quick Tip:
- 1–3 ft → Small waves, great for beginners.
- 3–6 ft → Shoulder- to head-high surf, good for intermediates.
- 6+ ft → For advanced surfers only.
2. Swell Period: The Power Behind the Wave
The swell period (in seconds) measures the time between wave crests. It’s one of the most important—and most overlooked—factors in surf forecasting.
Longer periods mean more energy and cleaner, more powerful waves.
- Short-period swell (5–8 sec): Wind swell, short and choppy.
- Medium-period swell (9–12 sec): Fun, rideable waves.
- Long-period swell (13–20+ sec): Powerful groundswells that travel from distant storms and produce hollow, high-quality waves.
Pro Tip: If you see a 3 ft swell with a 16-second period, expect overhead sets—it’ll be much more powerful than it looks on paper.
3. Swell Direction: The Angle That Matters
Swell direction shows where the waves are coming from—N (north), S (south), E (east), or W (west). Every surf break faces a particular direction, so not all swells work everywhere.
Example:
- A southwest swell might light up a beach in California but miss one facing northeast.
- Reef and point breaks depend heavily on the right direction for waves to wrap and break perfectly.
Pro Tip: Learn your local break’s “sweet spot” swell direction. Most surf reports include this info once you’ve surfed a spot a few times.
4. Wind: Friend or Foe
Wind can make or break your session—literally.
- Offshore wind: Blows from land to sea, holding waves open and creating clean, glassy faces.
- Onshore wind: Blows from sea to land, making waves crumble and choppy.
- Cross-shore wind: Blows sideways, creating uneven conditions.
When to surf:
- Mornings usually have lighter, offshore winds.
- Afternoons tend to get windier—unless it’s glassy or calm all day.
5. Tide: The Hidden Factor
Tides affect how and where waves break. Some spots are best at low tide, others at mid or high tide.
Low Tide: Exposes reefs and sandbars, creating faster, hollower waves—but can be dangerous at shallow breaks.
Mid Tide: Often the most balanced—enough water for takeoffs with good shape.
High Tide: Softer, slower waves that sometimes lose power.
Pro Tip: Check surf reports to learn your break’s best tide window. Many apps show this visually on tide charts.
6. Surf Forecast Tools and Apps
Modern surfers have an advantage: detailed digital forecasts. The best tools include:
- Magicseaweed (MSW) – Visual charts and surf reports.
- Surfline – Live cams and detailed forecasts by region.
- Windy – Excellent for tracking wind and weather patterns.
- Stormsurf / Windguru – Great for analyzing long-range swell patterns.
Combine data from multiple sources for the most accurate results.
7. Local Knowledge Still Rules
Even the best forecast can’t replace experience. Spend time observing your local spots under different conditions. You’ll start to notice how small changes in swell direction or tide dramatically affect wave quality.
Ask locals, keep a surf journal, and log your sessions—it’s how pros build intuition over time.
8. Bonus: Reading Between the Lines
- A small swell with a long period often produces surprisingly fun waves.
- Don’t ignore secondary swells—they can create cross-peaks and add energy.
- Watch buoy data for real-time readings; it’s often more accurate than app predictions.
Final Thoughts
Learning to read surf forecasts is like learning a new language—the language of the ocean. Once you understand how swell, wind, and tide interact, you’ll surf smarter, score better waves, and waste less time guessing.
Forecasts guide you, but instinct perfects you. Combine both, and you’ll know when to chase the next swell—and when to just sit back and watch the horizon build.