🎯 How it works

One score.
Every wave.

SwellIQ takes the complexity of surf forecasting and turns it into a single number you can act on. Here's exactly how.

82
SwellScore — Epic conditions
A score of 82 means the surf is excellent today. The swell is hitting at the right angle, the wind is offshore, and the tide is in the ideal window. Go surf.
The basics

What is the SwellScore?

The SwellScore is a 0–100 rating that tells you exactly how good the surf is at any spot, right now. It's not a guess or a vibe — it's calculated from live wave, wind, and tide data pulled from multiple independent sources and compared against each spot's specific ideal conditions.

A 90+ is all-time conditions. A 70–89 is a great day worth driving to. A 50–69 is solid, worth paddling out. Below 40? You might want to check the forecast and wait for the next swell.

The formula

How the score is calculated

Five factors go into every SwellScore. Each is weighted based on how much it actually impacts the quality of a surf session.

🌊
+30 pts
Wave Height
We measure actual swell size in feet. Each spot and skill level has an ideal range — too small or too big both lower the score.
⏱
+20 pts
Swell Period
Period (seconds between waves) determines wave power and shape. A 16-second swell is a groundswell — clean, powerful, organized. A 6-second swell is choppy windswell.
🧭
+20 pts
Swell Direction
Every break has an ideal swell angle. Pipeline needs northwest. J-Bay needs southwest. A swell hitting from the wrong direction can ruin an otherwise great forecast.
💨
+20 pts
Wind
Offshore winds (blowing from land to sea) groom waves perfectly. Onshore winds blow spray back, creating messy choppy conditions. Wind strength matters too.
🌊
+10 pts
Tide
Many breaks only work properly at specific tides. Some spots are best at low tide over shallow reef. Others need a pushing mid tide. We factor in each spot's preference.
Real examples

Why one spot scores a 28 vs an 87

Same spot, different conditions. Here's exactly why the score changes.

87
Lower Trestles
Epic
5ft · 14s NW swell · Offshore SE winds · Mid tide
Perfect northwest swell direction for Trestles, powerful 14-second period, light offshore winds grooming the face, and ideal mid tide. Every factor is aligned.
52
Lower Trestles
Good
4ft · 9s SW swell · Side-offshore winds · Low tide
Decent size but the swell direction is south — not ideal for Trestles which wants northwest. The shorter period makes it less powerful. Still rideable, just not firing.
28
Lower Trestles
Poor
2ft · 7s · Strong onshore NW winds
Small, short-period windswell blown apart by onshore winds. This is the kind of day most experienced surfers stay home — or find a protected spot.
AI personalization

Your score, built for you

Here's the thing Surfline doesn't do: the same conditions mean completely different things depending on who's surfing. A 2ft day at your local beach break could be perfect for a beginner and a waste of time for an advanced surfer. SwellIQ accounts for this.

91
Beginner
2ft, clean, light winds
Perfect. Safe, manageable waves to practice on. A 2ft day at a beach break is a beginner's dream.
68
Intermediate
2ft, clean, light winds
Good, but not exciting. An intermediate surfer can ride this easily, but would prefer more size to work with.
34
Advanced
2ft, clean, light winds
Below average. An advanced surfer wants power and size. 2ft is barely worth paddling out for at their level.

Set your skill level in your profile and every score across every spot will be recalculated specifically for you. The general score is always visible too — so you can see both.

The data

Where the data comes from

We don't rely on a single source. SwellIQ pulls from 5+ independent data providers simultaneously, then builds a consensus. More sources means higher confidence and more accurate scores.

Open-Meteo / ECMWF
Free · Always on
European Centre for Medium-Range Weather Forecasts. 9km resolution global wave and wind model. Our backbone source.
Stormglass
Paid · 9 ocean models
Aggregates 9 independent models including NOAA, DWD, ICON, and FMI. High-confidence consensus data.
WorldTides
Paid · Global tides
Precise tide predictions for every spot worldwide. Essential for scoring tide-sensitive breaks accurately.
NOAA Buoys
Free · Real instruments
Live readings from physical buoys in the ocean. No model — actual measured wave height, period, and direction.
Windy / GFSWave
Paid · NOAA GFS wave model
Additional wave model and webcam data from Windy. Adds swell separation — wind swell vs ground swell — to the analysis.

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