GlassyLinesHow We Forecast
The question is simple: when will the surf be worth a look? We bring together public ocean and weather data to give you a clear picture of size, conditions, and the best time to paddle out.
Start With the Swell
We look at the waves heading toward a spot: how big they are, where they come from, and how far apart they are. That helps us estimate the size of the surf you could see at the beach.
Put It in Beach Context
The same swell can look different at two beaches. We consider the direction a spot faces, the tide, and the wind. Offshore wind often helps keep wave faces clean; onshore wind can make them bumpy. Wind strength matters, too.
Make the Day Easy to Read
Each hour gets an estimated surf size and a conditions rating. The chart combines the two so you can see how the day changes. Confidence bars give a quick sense of how certain the forecast is; forecasts further into the future are usually less certain.
Check Against the Real World
Buoy readings and reports from surfers help us compare expectations with what actually happened and improve future forecasts. Offshore buoy waves are different from waves breaking at the beach, so we keep that distinction in mind.
Public Data, Useful Surf Reports
Free public forecasts, tide predictions, and ocean observations are a big part of what makes GlassyLines possible. Our sources include:
- Open-Meteo
Ocean and weather forecasts, including swell and wind from services such as ECMWF and NOAA.
- NOAA & the National Weather Service
Public wind forecasts and tide predictions for supported US locations.
- NOAA Buoys
Real measurements from offshore buoys help us check what is happening in the water.
Sandbars, local weather, and conditions at the beach can change quickly. Use the forecast to plan, then check the water when you arrive.