Beaufort Scale

anemometer

Beaufort Scale for Land Areas

Below is a table showing the Beaufort Scale with speeds in knots, miles per hour and kilometers per hour.

Please note that these are these are mean speeds, usually over 10 min by convention, and not gusts.
The quoted wind speed is that measured at 10 m above ground, not at the surface (which, at 2 m, may be only 50-70% of these figures)

Wind Force
Description
Speed
Specifications
km/h
mph
knots
0 Calm <1 <1 <1 Smoke rises vertically
1 Light Air 1-5 1-3 1-3 Direction shown by smoke drift but not by wind vanes
2 Light Breeze 6-11 4-7 4-6 Wind felt on face; leaves rustle; wind vane moved by wind
3 Gentle Breeze 12-19 8-12 7-10 Leaves and small twigs in constant motion; light flags extended
4 Moderate Breeze 20-28 13-18 11-16 Raises dust and loose paper; small branches moved.
5 Fresh Breeze 29-38 19-24 17-21 Small trees in leaf begin to sway; crested wavelets form on inland waters.
6 Strong Breeze 38-49 25-31 22-27 Large branches in motion; whistling heard in telegraph wires; umbrellas used with difficulty.
7 Near Gale 50-61 32-38 28-33 Whole trees in motion; inconvenience felt when walking against the wind.
8 Gale 62-74 39-46 34-40 Twigs break off trees; generally impedes progress.
9 Strong Gale 75-88 47-54 41-47 Slight structural damage (chimney pots and slates removed).
10 Storm 89-102 55-63 48-55 Seldom experienced inland; trees uprooted; considerable structural damage
11 Violent Storm 103-117 64-72 56-63 Very rarely experienced; accompanied by widespread damage.
12 Hurricane 118 plus 73 plus 64 plus Devastation