Determining Wind Speed

Land Beaufort Scale

The Beaufort scale was long in use as a system for estimating wind speeds. It was introduced in 1806 by Admiral Sir Francis Beaufort (1774-1857) of the British navy to describe wind effects on a fully rigged man-o-war sailing vessel, and it was later extended to include descriptions of effects on land features as well.

Force    Speed (mph)     Indicators
0                0                   Smoke rises vertically  break out a no wind glider
1             1 - 3                 Smoke drift indicates wind direction  ultra light sport kite
2             4 - 7                 Wind felt on face; leaves rustle  ideal for sport kites
3             8 - 12               Leaves, small twigs in constant motion  any thing will fly
4             13 - 18             Dust and leaves raised up, branches move  reaching the top end
5             19 - 25             Small trees begin to sway  time to start packing up
6             26 - 31             Large branches of trees in motion   time to take up chess