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Windspeed conversions


Here you can convert between units. Type a number into a textbox below and then click outside it. Please note that Beaufort-values are between 0 and 12.
Beaufort:       m/s:     km/h:     knots:   miles/h:

Beaufort-values corresponds to windspeed intervals. If a number is entered in the Beaufort-box, other boxes will display appropriate median values for that Beaufort-number, approximated to the nearest integer. If a number is entered in other boxes, the Beaufort-box will display the approximated Beaufort-value. This approximation inevitable leads to a slight inaccuracy in the calculations. The figure on the right loosely shows the relationship between m/s and a few Beaufort-values.

The prerequisites of the calculations above are:
Below is a detailed table with comparison between Beaufort-values, average windspeed and the median for the average windspeed in m/s, km/h, knots and mph. Beaufort - m/s comparison

Windspeed classification


To ease the understanding of the m/s measurement, the following table can be used.
Windspeed in m/s Description
<5 Very slow wind
5-10 Rather slow wind
10-20 Considerable wind, may lead to difficulties
20-30 Very windy, caution is advised
>30 Extreme wind, dangerous

Comparison with Beaufort-values

Windforce* Average windspeed** Median of av. windspeed
Beaufort Name m/s km/h knots miles/h    m/s   km/h knots miles/h
0 Calm

0-0,2

< 1

< 1

<1 0,0 0,0 0,0 0,0
1 Light air

0,3-1,5

1-5

1-3

1-3 0,8 3,0 1,6 1,9
2 Light breeze

1,6-3,3

6-11

4-6

4-7 2,4 8,5 4,6 5,3
3 Gentle breeze

3,4-5,4

12-19

7-10

8-11 4,3 15,6 8,4 9,7
4 Moderate breeze

5,5-7,9

20-28

11-16

13-18 6,7 24,1 13,0 15,0
5 Fresh breeze

8,0-10,7

29-38

17-21

19-24 9,3 33,6 18,2 20,9
6 Strong breeze

10,8-13,8

39-49

22-27

25-31 12,3 44,2 23,9 27,5
7 Near gale

13,9-17,1

50-61

28-33

32-38 15,5 55,7 30,1 34,6
8 Gale

17,2-20,7

62-74

34-40

39-46 18,9 68,1 36,8 42,3
9 Strong gale

20,8-24,4

75-88

41-47

47-54 22,6 81,3 43,9 50,5
10 Storm

24,5-28,4

89-102

48-55

55-63 26,4 95,2 51,4 59,1
11 Violent storm

28,5-32,6

103-117

56-63

64-74 30,5 109,8 59,3 68,2
12 Hurricane

>= 32,7

>= 118

>= 64

>=75 ... ... ... ...
* Windforce measured in Beaufort-values is not an objective observation of windspeed, but rather a subjective one, based on the impact of the wind on the environment. ** This empirical relation between windforce, estimated on the Beaufort-scale, and the windspeed is based on the 10 minute average of the windspeed. In reality, windspeeds can vary a lot in that time. As a result, windgusts can not be measured with the Beaufort-scale. Windspeeds are now generally measured with anemometers, which continuously record the momentary windspeed, i.e. windgusts, that can vary a great deal from a 10 minute average windspeed an therefore bear no relations to the Beaufort-scale.