Archive - Beaufort Wind Scale

Beaufort
Number

Wind
Speed

Description

Deep Sea
Criterion

Wave
Height (m)

0

<1

Calm

Sea like a mirror

-

1

1-3

Light air

Ripples

-

2

4-6

Light breeze

Small wavelets, glassy crests

0.15

3

7-10

Gentle breeze

Large wavelets, foam

0.60

4

11-16

Moderate breeze

Small waves, frequent white horses

1.00

5

17-21

Fresh breeze

Moderate waves, many white horses, spray

1.80

6

22-27

Strong breeze

Large waves, white foam crests

3.00

7

28-33

Near gale

Breaking waves, foam streaks

4.00

8

34-40

Gale

High waves, spindrift

5.50

9

41-47

Strong gale

High waves, dense foam streaks, spray

7.00

10

48-55

Storm

Very high waves, overhanging crests, white sea

9.00

11

56-63

Violent storm

Exceptionally high waves, medium ships lost to view

11.30

12

64+

Hurricane

Air filled with foam and spray, little visibility

13.70