Understanding marine weather is a core boating skill. The water amplifies every weather condition. Here's how to read a forecast and decide whether to go.
Wind is the most important variable. Under 10 knots is comfortable for almost any boat. 10-15 knots is moderate, small boats should stay in protected waters. 15-20 knots means building seas, less experienced boaters should stay in. Over 20 knots is for experienced crews in capable boats only.
Sea state depends on wind speed, duration, and fetch (distance over water). Seas take hours to build and hours to calm after wind drops. A morning forecast of 5 knots building to 15 by afternoon means you should plan to be back early.
Tides affect water depth (critical for draft), current strength and direction (affects fuel burn and speed over ground), and inlet conditions. Outgoing tide against incoming wind creates steep, dangerous breaking seas at inlets.
Know your tide window. If you need 4 feet of water to clear a bar, check when the tide gives you that depth and plan your transit accordingly.
Rising pressure = improving weather. Falling pressure = deteriorating weather. Rapid drops (more than 2 mb in 3 hours) signal approaching storms.
This is the most reliable single indicator of near-term weather changes. Check it before every trip.
The Go/No-Go decision framework: Check wind speed and direction. Check wave height and period. Check for NOAA alerts or warnings. Check tides for your route. Check visibility forecast. If any factor is marginal, the answer is No-Go.
Informed Boating's forecast page runs a multi-model Go/No-Go analysis automatically. Four weather models vote on whether conditions are safe for your boat size.
Get a personalized Go/No-Go decision at informedboating.com/forecast, free, no signup required.
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