Beaufort number Force |
Average wind speed (km/h / mph) | Description | Wave height | Sea conditions | |
|---|---|---|---|---|---|
| m | ft | ||||
| 0 | 0 / 0 |
Calm | 0 | 0 | Flat. |
| 1 | 4 / 2 |
Light air | 0.1 | 0.33 | Ripples without crests. |
| 2 | 9 / 6 |
Light breeze | 0.2 | 0.66 | Small wavelets. Crests of glassy appearance, not breaking |
| 3 | 17 / 11 |
Gentle breeze | 0.6 | 2 | Large wavelets. Crests begin to break; scattered whitecaps |
| 4 | 24 / 15 |
Moderate breeze | 1 | 3.3 | Small waves. |
| 5 | 35 / 22 |
Fresh breeze | 2 | 6.6 | Moderate (1.2 m) longer waves. Some foam and spray. |
| 6 | 44 / 27 |
Strong breeze | 3 | 9.9 | Large waves with foam crests and some spray. |
| 7 | 56 / 35 |
Near gale | 4 | 13.1 | Sea heaps up and foam begins to streak. |
| 8 | 68 / 42 |
Gale | 5.5 | 18 | Moderately high waves with breaking crests forming spindrift. Streaks of foam. |
| 9 | 81 / 50 |
Strong gale | 7 | 23 | High waves (2.75 m) with dense foam. Wave crests start to roll over. Considerable spray. |
| 10 | 96 / 60 |
Storm | 9 | 29.5 | Very high waves. The sea surface is white and there is considerable tumbling. Visibility is reduced. |
| 11 | 111 / 69 |
Violent storm | 11.5 | 37.7 | Exceptionally high waves. |
| 12 | N/A |
Hurricane | 14+ | 46+ | Huge waves. Air filled with foam and spray. Sea completely white with driving spray. Visibility very greatly reduced. |
Did you know...
Admiral Francis Beaufort was Irish and worked in British Navy square rigger ships when he made the scale of wind strengths based on what the sea looked like in 1806. The Chinese made the scale up to Force 17 last year because they had a terrible hurricane!
WIND
Wind is moving air. But it acts like water. It always has to be level. So it moves to and from areas of different pressure to try to keep the pressure equal and thats the wind you feel. If you stand with your back to the wind the centre of the pressure that the wind is swirling around will be to your left - so you'll know if the weather is going away from you or not...
The BEAUFORT SCALE is how we measure wind.
WEATHER
Put everything together and you have weather. Sun, wind, rain. The stronger the wind is the colder you become very quickly - especially when you are wet. . This is windchill.
If the sun is shining - even on a windy day you will get more sunburned near water because the rays are reflected back up from the water too.
If you get sunburned when you are young you'll probably get cancer in a few years.
SLIP! SLAP! SLOP! Slip on a T-shirt, slap on a hat and slop on some sun-cream. Factor 35 at least.
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