Learn how to read Windguru, compare GFS and ECMWF wind models, and understand wind direction, gusts, and swell to plan your windsurf sessions with confidence.
Reading a wind forecast correctly is probably the single most important skill a windsurfer can develop off the water. A good forecast read saves you from flat-water disappointments and puts you on the water when conditions are firing. The two most popular tools for windsurfers are Windguru and Windy, and both pull data from numerical weather models — primarily GFS and ECMWF.
GFS (Global Forecast System) is the American model. It updates every 6 hours and is free, which is why most forecast sites default to it. It has a resolution of about 25 km and is generally reliable up to 3-4 days out. Beyond that, accuracy drops quickly. ECMWF (European Centre for Medium-Range Weather Forecasts) is the European model. It runs at a finer resolution, updates twice daily, and is widely considered the more accurate of the two — especially for medium-range forecasts of 5-7 days. However, it is behind a paywall on many platforms.
When you look at a Windguru table, the key rows to focus on are wind speed, wind gusts, and wind direction. Wind speed tells you the average expected force. Gusts tell you how much variation to expect — a big gap between the two means gusty, less comfortable conditions. Wind direction determines whether your spot will work: an offshore wind at your beach might mean perfect side-shore conditions at another spot 20 km away.
Beyond wind, pay attention to swell data if you are wave sailing. Swell height, period, and direction tell you whether waves will be present and rideable. A 1.5 m swell at 12 seconds from the northwest is very different from a 1.5 m swell at 6 seconds from the south — the former produces clean, spaced-out waves, while the latter is messy chop.
A practical tip: always compare at least two models before committing to a session. If GFS says 20 knots and ECMWF says 12, the truth is probably somewhere in between — but lean toward ECMWF if you have to pick one. Also check the forecast trend over multiple updates: if each new run keeps increasing the wind, conditions are likely converging toward a stronger day.
