Wind Speed

Wind Speed:


DescriptionWind SpeedLand ConditionsSea Conditions
0Calm< 1 km/hCalm. Smoke rises vertically.Flat. Wave Height 0m.
1Light Air1.1 – 5.5 km/hSmoke drift indicates wind direction.
Wind vanes cease moving.
Ripples without crests.  Wave height 0 – 0.2m.
2Light Breeze5.6 – 11 km/hWind felt on exposed skin.
Leaves rustle and wind vanes begin to move.
Small wavelets. Crests of glossy appearance, not breaking. Wave height 0.2 – 0.5m.
3Gentle Breeze12 – 19 km/hLeaves and small twigs constantly moving, light flags extended.Large wavelets. Crests begin to break, scattered whitecaps. Wave height 0.5 – 1m.
4Moderate Breeze20 – 28 km/hDust and loose paper raised. Small branches begin to move.Small waves with breaking crests. Fairly frequent whitecaps. Wave height 1 – 2m.
5Fresh Breeze29 – 38 km/hBranches if a moderate size move.  Small trees in leaf begin to sway.Moderate waves of some length. Many whitecaps. Small amounts of spray. Wave height 2 – 3m.
6Strong Breeze39 – 49 km/hLarge branches in motion. whistling heard in overhead wires. Umbrella use becomes difficult. Empty plastic garbage cants tip over.Long waves begin to form. White foam crests are very frequent. Some airborne spray is present. Wave height 3 – 4m.
7High Wind, Moderate Gale, Near Gale50 – 61 km/hWhole trees in motion. Effort needed to walk against the wind.Sea heaps up. Some foam from breaking waves is blown into streaks along wind direction.  Moderate amounts of airborne spray. Wave height 4 – 5.5m
The Beaufort Scale is an empirical measure that relates wind speed to observed conditions at sea or on land. Its full name is the Beaufort Wind Force Scale. The scale was devised in 1805 by Francis Beaufort (later Rear Admiral Sir Francis Beaufort), an Irish-born Royal Navy officer, while serving on HMS Woolwich. It was officially adopted in the 1830’s and was first used during Darwin’s voyage on HMS Beagle. The complete scale extends to Force 12 which is well in excess of the safe kite flying range.