Marine Weather: how to estimate weather conditions?

When sailing, here is how to estimate wind speed and wave height. For wind, the Beaufort scale must be taken into account and for wave height, the Fédération des Industries Nautiques has created an explanatory diagram.

Chloé Torterat Published on April 5, 2019

Beaufort Wind Speed (BF) is the average actual wind speed over a 10-minute period at sea level.

Here is the Beaufort scale published by the World Meteorological Organization (WMO).

The gusts are about 1.3 times the average wind above 25 knots.

The anemometer on board measures the apparent wind, which vectorially adds the boat speed and wind speed, instantly.

European regulations use the significant wave height (H 1/3) which is the average height over a given period of one third of the highest waves.

It reflects the wave height estimated by an observer.

The significant wave height is related to wind ("wind sea"), and excludes shoreline and current effects (breaking near the shore, raz)

Here is a diagram illustrating this notion of significant height:

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