Advanced passage planning and weather intelligence for the global cruising community. Whether you're under power or sail, AI Passage Plan is built by cruisers, for cruisers.
🧭 How to Read the Map
Each marker shows a multi-day forecast for that location. The colored dots represent the worst conditions forecast for that day on your heading:
🟡 CAUTIONMarginal conditions — might be sporty for some and scary to others. Review the details and decide for yourself.
🔴 WAITPoor or dangerous conditions. Not recommended.
⚫ No dataForecast unavailable for this date.
Tap any marker to see the full forecast breakdown by day and direction.
💨 Apparent Wind
This tool calculates apparent wind — the wind you actually feel on a moving boat — not just the forecast true wind. At 6 knots boat speed, a 15kt headwind becomes 21kt apparent. A 15kt tailwind becomes 9kt apparent. This gives you a more realistic picture of what sailing conditions will actually feel like.
🌊 Sea State
Sea state is scored based on wave height, period, and angle relative to your heading:
GOODComfortable. Manageable waves for most boats.
FAIRNoticeable motion. Acceptable but not ideal.
POORRough. Consider waiting for better conditions.
DANGEROUSSevere. Do not depart.
Flag pills in the forecast indicate specific hazards:
CALMLight wind and flat seas.
CHOPPYShort steep wind waves.
SQUAREWaves hitting beam-on.
BEAM SEASWind on the beam.
BLOWN OUTWind and wave conditions severely degraded.
CAPE EFFECTWind accelerated around a cape.
🌙 Moon Strip
The arc around each moon emoji shows what fraction of that night the moon is above the horizon. A full circle means the moon is up all night. The color reflects illumination — bright yellow near full moon, dimmer near new moon. The tide bar below shows tidal strength — green is neap (weak tides), yellow is transitional, red is spring (strong tides). Hover over any moon card for details.
📡 Data
Wind forecasts use ECMWF IFS 9km — the same model used by professional mariners, updated 4× daily. Wave data uses the GFS wave model.
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⚠️ Disclaimer
This tool is designed to help experienced sailors make informed decisions. It is not a substitute for official weather forecasts, NOAA marine forecasts, or professional weather routing. Conditions can change rapidly at sea. Always consult multiple sources before departing. The creator of this tool assumes no responsibility for decisions made based on this forecast. You are responsible for your vessel and crew.
