La Crosse Technology WS-9035TWC instruction manual Beaufort Number Or Force Wind Speed Description

Beaufort Number

or Force

Wind Speed

Description Effects Land / Sea

0

1

2

3

4

5

6

7

8

mph	km/hr	knots
<1	<1	<1
1-3	1-5	1-3
mph	kph	knots
4-7	6-11	4-6
mph	kph	knots
8-12	12-19	7-10
mph	kph	knots
13-18	20-28	11-16
mph	kph	knots
19-24	29-38	17-21
mph	kph	knots
25-31	39-49	22-27
mph	kph	knots
32-38	50-61	28-33
mph	kph	knots
39-46	62-74	34-40
mph	kph	knots

Calm

Light Air

Light Breeze

Gentle Breeze

Moderate Breeze

Fresh Breeze

Strong Breeze

Moderate or Near Gale

Gale or Fresh Gale

Still, calm air, smoke will rise vertically.

Water is mirror-like.

Rising smoke drifts, wind vane is inactive.

Small ripples appear on water surface.

Leaves rustle, can feel wind on your face, wind vanes begin to move.

Small wavelets develop, crests are glassy.

Leaves and small twigs move, light weight flags extend.

Large wavelets, crests start to break, some whitecaps.

Small branches move, raises dust, leaves and paper.

Small waves develop, becoming longer, whitecaps.

Small trees sway.

White crested wavelets (whitecaps) form, some spray.

Large tree branches move, telephone wires begin to "whistle", umbrellas are difficult to keep under control.

Larger waves form, whitecaps prevalent, spray.

Large trees sway, becoming difficult to walk.

Larger waves develop, white foam from breaking waves begins to be blown.

Twigs and small branches are broken from trees, walking is difficult.

Moderately large waves with blown foam.

13