# Estimating Wind Speeds Using The Beaufort Scale

Most pilots become pretty adept at estimating wind speeds from the wind sock at the airfield, but this isn’t the most reliable method.

After all, wind socks differ and what may appear to be a light wind at our home airfield could be a stinker at an aerodrome we are planning to visit.

For sailors it’s a much easier task of using The Beaufort Scale (below), and this is where I believe that both aviation and sailing should use the same method.

The Beaufort scale is far more reliable than using a wind sock, and once you’ve practiced using it, you will wonder why it took you so long!

Here’s the scale with it’s accompanying force and wind speed. To use it, just look at the Description column and estimate which most closely fits the conditions you are experiencing. Then read off the relevant wind speed.

For most sailors a Force 6 is the limit of there capabilities (or series!), whilst for most pilots a Force 5 is pushing it.

Have a go at using the scale below to estimate your own wind speeds.

 Wind Force Description km/h mph knots Description 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