Beaufort wind scale: wind speed, force and wave height

Wind speed is the mean at 10 m above the sea. Wave heights are typical for the open sea far from land; near the coast and in shallow water seas are different.

Result

Beaufort force6

DescriptionStrong breeze

Probable wave height3.0 m

How it is calculated

Ranges as published by the WMO: force 0 below 1 kn, 1: 1–3, 2: 4–6, 3: 7–10, 4: 11–16, 5: 17–21, 6: 22–27, 7: 28–33, 8: 34–40, 9: 41–47, 10: 48–55, 11: 56–63, 12: 64 kn and more.

Reference only. The maker's manual and class rules take priority.

Reference table

Beaufort force	Description	kn	m/s	Probable wave height, m
0	Calm	< 1	< 0.3	0.0
1	Light air	1–3	0.5–2.1	0.1
2	Light breeze	4–6	2.1–3.6	0.2
3	Gentle breeze	7–10	3.6–5.7	0.6
4	Moderate breeze	11–16	5.7–8.7	1.0
5	Fresh breeze	17–21	8.7–11.3	2.0
6	Strong breeze	22–27	11.3–14.4	3.0
7	Near gale	28–33	14.4–17.5	4.0
8	Gale	34–40	17.5–21.1	5.5
9	Strong gale	41–47	21.1–24.7	7.0
10	Storm	48–55	24.7–28.8	9.0
11	Violent storm	56–63	28.8–32.9	11.5
12	Hurricane force	≥ 64	≥ 32.9	14.0

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