Key Takeaways
- Surf forecasts are ±1-2 feet accurate for 0-3 days. Quiver's ML corrections improve raw NOAA output by 59% at specific beaches.
- Global models miss local effects. Quiver's ML learns each beach's systematic biases and corrects for them — see live metrics at /forecast-accuracy.
- Plan sessions from the 3-day window. Always cross-check the forecast against buoy data before paddling out.
The Short Answer
NOAA's WaveWatch III global wave model is accurate within ±1-2 feet for significant wave height and ±2-3 seconds for period, 0-3 days out. Beyond 5 days, accuracy drops to ±3+ feet. Quiver's per-beach XGBoost ML corrections — trained on 30,000+ buoy observations from CDIP and NDBC — achieve a 90.4% directional match rate and 59% improvement over raw NOAA baseline. No forecast is perfect; buoys are always the ground truth.
The Short Answer
Where Forecasts Are Accurate — and Where They Fail
WaveWatch III runs at 0.5° resolution (~30 miles per grid cell). It captures open-ocean swells well but misses the "last mile" — local bathymetry (underwater canyons, reefs, sandbars), coastal wind patterns, and swell refraction around headlands. That's why buoy readings at La Jolla's Scripps Pier can differ from WaveWatch III by 1-3 feet: the Scripps Canyon focuses and amplifies certain swell angles in ways the global model can't resolve.
Quiver's ML layer fixes this. Per-beach XGBoost models learn the systematic bias at each break — when the model consistently over-predicts at your spot, ML corrects it. This is evaluated against holdout data (data the model never saw during training) to prevent overfitting. The public accuracy dashboard at quiversurf.app/forecast-accuracy shows real-time metrics by region and beach.
Global models miss local effects. Quiver's ML learns each beach's systematic biases and corrects for them — see live metrics at /forecast-accuracy.
What This Means for Your Session
Trust the 0-3 day forecast window for planning sessions. Use the 5-7 day view to track incoming swell systems, but don't commit to plans based on it — too much can change. Always cross-check the forecast against real-time buoy data 1-3 hours before your session. If the nearest NDBC buoy shows 3 feet but the forecast says 5 feet, the swell hasn't arrived yet or the model over-predicted. Build local knowledge: after 20+ sessions comparing Quiver's forecast to what you actually see, you'll develop an intuitive calibration for your break that no model can replace.
