Windy
Windy is the most popular weather visualisation tool among sailors. It aggregates multiple weather models and presents them as an interactive, animated map. Understanding which model to read — and when — is what separates a good forecast from a dangerous guess.
Quick Facts
- Price: Free (Premium from ~$20/year)
- Platforms: Web, iOS, Android
- Best for: Offshore planning, model comparison
- Premium adds: Extra models, 1-hr forecasts, alerts
Weather Models Explained
A weather model is a computer simulation of the atmosphere. Each model uses different maths, different input data, and runs at different resolutions. No single model is "best" everywhere — the trick is knowing which one to trust for your area and timeframe.
| Model | Coverage | Resolution | Updates | Best For |
|---|---|---|---|---|
| GFS | Global | ~22 km | 4x/day | 3-7 day route planning, free baseline |
| ECMWF | Global | ~9 km | 2x/day | Most accurate 5-10 day outlook |
| ICON | Europe focus | ~7 km | 4x/day | North Sea, Baltic, Med coastal |
| AROME | Western Med | ~1.3 km | 4x/day | Short-range Med sailing (0-48 hrs) |
| HRRR | US only | 3 km | Hourly | 0-18 hr nowcasting, US coastal |
| NAM | North America | ~12 km | 4x/day | 1-3 day US & Caribbean |
Which Model Should You Use?
Mediterranean Sailing
Start with ECMWF for the 5-day outlook, then switch to ICON or AROME as you get within 48 hours. AROME is particularly good at resolving land/sea breezes and katabatic winds that GFS misses entirely in places like Croatia or the Greek islands.
Atlantic Crossings & Offshore
ECMWF is king for offshore. It consistently outperforms GFS on synoptic-scale systems (lows, fronts, trade wind patterns). Compare both and when they disagree significantly, respect the ECMWF forecast and consider waiting for the next model run.
UK & Northern Europe
Use ICON for 0-3 day coastal forecasts — it handles the complex coastline and shallow-water effects of the North Sea and English Channel well. For longer range, fall back to ECMWF.
Caribbean & US Coast
GFS and NAM are your primary models here. For day-of conditions along the US coast, HRRR is unbeatable with its hourly updates and 3 km resolution. For hurricane tracking, always cross-reference the NHC official forecast.
Windy Pro Tips for Sailors
Always compare at least two models.If GFS says 15 knots and ECMWF says 30, don't split the difference — figure out why they disagree and prepare for the worse case.
Use the "Waves" layer for swell.Wind speed alone doesn't tell you the sea state. A 15-knot breeze against a 2m leftover swell makes for a miserable sea.
Check the "Meteogram" view. Tap any point on the map and open the meteogram — it shows wind, gusts, precipitation, pressure, and temperature over time in one chart. Much easier to spot weather windows.
Set alerts for your route. Windy Premium lets you set weather alerts for specific locations. Set them for your departure port, waypoints, and destination.
Pressure isobars tell the real story.Enable the pressure layer — tightly packed isobars mean strong wind. If you see isobars squeezing together over the next few days, that's your cue to find a sheltered anchorage.
Free vs Premium
Free
- GFS, ICON, and other free models
- 3-hourly forecast data
- Wind, rain, temperature, pressure layers
- Meteograms and point forecasts
- Wave and swell data
Premium (~$20/year)
- ECMWF, AROME, NEMS, and other premium models
- 1-hourly forecast resolution
- Weather alerts for saved locations
- Better hurricane and storm tracking
- Ad-free experience
For serious sailing, Premium is well worth the money. ECMWF access alone justifies the cost — it's the model professional forecasters trust most.