Beaufort Scale

Summary of Beaufort Scale

A scale of wind force at sea, adjusted for the angle between the direction of the wind and the ship's course and speed. The figure shows how wind force is expressed. Beaufort Scale

Beaufort Number Sea Conditions Knots

0 Calm less than 1

1 Light air 1-3

2 Light breeze 4-6

3 Gentle breeze 7-10

4 Moderate breeze 11-16

5 Fresh breeze 17-21

6 Strong breeze 22-27

7 Moderate Gale 28-33

8 Fresh gale 34-40

9 Strong gale 41-47

10 Whole gale 48-55

11 Storm 56-65

12 Hurricane over 65

(Main Author: William J. Miller)