Knots

Km/h

Beaufort Scale

Light

1 - 9

1 - 16

Wind felt on face; leaves rustle.

Moderate

10 - 13

17 - 24

Raises dust and loose paper; small branches are moved.

Fresh

14 - 19

25 - 35

Small trees in leaf begin to sway.

Strong

20 - 30

36 - 56

Large branches in motion; umbrellas used with difficulty.

Near Gale

31 - 34

57 - 63

Whole trees in motion; inconvenience felt when walking against wind.

Gale

35 - 40

64 - 74

Breaks twigs off trees; generally impedes progress.

Strong Gale

41 - 47

75 - 87

Slight structural damage occurs (chimney - pots removed)