Beaufort Scale

Anemometer

Anemometer

BEAUFORT WIND SCALE FOR LAND AREAS


• Make your observations in an open location, e.g. school field.
• Use the scale below to estimate wind speed.
• Enter CALM if there is no wind.

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