Beaufort Scales

Force
Knots
MPH
Name
Conditions

0

< 1

< 1

Calm

Sea like a mirror.

1

1-3

1-4

Light air

Ripples only.

2

4-6

5-7

Light breeze

Small wavelets (< 1 ft) crests have a glassy appearance.

3

7-10

8-11

Gentle breeze

Large wavelets (2 ft) crests begin to break.

4

11-16

12-18

Moderate breeze
Small waves (1-3 ft) some whitecaps.

5

17-21

19-24

Fresh breeze

Moderate waves (4-6 ft) many whitecaps.

6

22-27

25-31

Strong breeze

Large waves (10 ft) probably some spray.

7

28-33

32-38

Near gale

Mounting sea (12-14 ft) with foam blown in streaks downwind.

8

34-40

39-46

Gale

Moderately high waves (18-20 ft) crests break into spindrift.

9

41-47

47-54

Strong gale

High waves (23-28 ft) dense foam, visibility affected.

10

48-55

55-63

Storm

Very high waves (30 ft) heavy sea roll, visibility impaired. Surface generally white.

11

56-63

64-73

Violent storm

Exceptionally high waves (35 ft) visibility poor.

12

64+

74+

Hurricane

45 ft+ waves, air filled with foam and spray, visibility bad.



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