Wave Height

    Wave heights reported are the significant wave height. The significant wave height is the most commonly reported wave height. Mathematically, the significant wave height is defined as the average of the top third largest waves.

Max Wave

    Maximum wave height is the largest measured wave in a 10 minute period. When a maximum wave is greater than 2 times the significant wave height,the record is flagged as a freak wave.

Temperature -

    Water temperature is measured approximately 10 ft below the surface in 20 ft of water infront of the Mainland Sea Caves.

Period -

    Wave Period is how long between successive wave crests in seconds.

Wind -

    Wind data is downloaded from the NOAA website for the wind measured at Devil's Island (link below)

Devils Island NOAA

    Wind Direction is the direction the wind is coming from.

Beaufort Scale -

    The Beaufort Scale is an empirical method for relating wind speed and observed sea conditions. A further explanation can be seen at Wikipedia.




Wind Speed


Wave Height


Sea Conditions

0 Calm <1 0 Flat
1 Light air 1-3 0-1 Ripples without crests.
2 Light Breeze 4-7 1-2 Small wavelets. Crests of glassy appearance, not breaking.
3 Gentle Breeze 8-12 2-3.5 Large wavelets. Crests begin to break; scattered whitecaps.
4 Moderate Breeze 13-17 3.5-6 Small waves with breaking crests. Fairly frequent whitecaps.
5 Fresh Breeze 18-24 6-9 Moderate waves of some length. Many whitecaps. Small amounts of spray.
6 Strong Breeze 25-30 9-13 Long waves begin to form. White foam crests are very frequent. Some airborne spray is present.
7 High wind, moderate gale. 31-38 13-19 Sea heaps up. Some foam from breaking waves is blown into streaks along wind direction. Moderate amounts of airborn spray.
8 Gale 39-46 18-25 Moderately high waves with breaking crests forming spindrift. Well-marked streaks of foam are blown along wind direction. Considerable airborne spray.
9 Strong Gale 47-54 23-32 High waves whose crests sometimes roll over. Dense foam is blown along wind direction. Large amounts of airborne spray may begin to reduce visibility.
10 Storm, Whole Gale 55-63 29-41 Very high waves with overhanging crests. Large patches of foam from wave crests give the sea a white appearance. Considerable tumbling of waves with heavy impact. Large amounts of airborne spray reduce visibility.
11 Violent Storm 64-72 37-52 Exceptionally high waves. Very large patches of foam, driven before the wind, cover much of the sea surface. Very large amounts of airborne spray severely reduce visibility.
12 Hurricane >73 >46 Huge waves. Sea is completely white with foam and spray. Air is filled with driving spray, greatly reducing visibility.