| Force | Wind Description |
Speed Knots |
Speed Km/h |
Land | Water |
|---|---|---|---|---|---|
| 0 | Calm | 0 – 1 | 0 – 1 | Smoke rises vertically |
Water is like a mirror. Cannot sail. |
| 1 | Light Air | 1 – 3 | 1 – 5 | Smoke indicates direction. Not enough wind for vanes | Small ripples on water. Enough wind for a light Spinnaker |
| 2 | Light Breeze | 4 – 6 | 6 – 11 | Wind felt on face. Tree leaves start moving. Wind vanes indicate direction. | Small wavelets. Wind now fills sail. |
| 3 | Gentle Breeze | 7 – 10 | 12 – 19 | Small flags are extended. Leaves move constantly. | Large wavelets. Sailboats start to heel. |
| 4 | Moderate Breeze | 11 – 16 | 20 – 28 | Dust is raised by wind. Small branches start bending. | Good working breeze. Saiboats at hull speed, full sail. |
| 5 | Fresh Breeze | 17 – 21 | 29 – 38 | Small trees are reacting to wind. | Numerous whitecaps. Time to shorten sails. |
| 6 | Strong Breeze | 22 – 27 | 39 – 49 | Wind now whistles. Most branches in trees moving. | Whitecaps eveywhere. Sailboats start to head ashore. |
| 7 | Near Gale | 28 – 33 | 50 – 61 | Whole trees now move. | Much bigger waves. Sailboats remain at harbour. |
| 8 | Gale | 34 – 40 | 62 – 74 | Small branches are starting to break. Walking in now hard. | Foam in well marked streaks. All boats now head in. |
| 9 | Strong Gale | 41 – 47 | 75 – 88 | Buildings are starting to show small damage. | Low visibility due to spray. |
| 10 | Storm | 48 – 55 | 89 – 102 | Dangerous Situation | High seas over 8 metres |
| 11 | Violent Storm | 56 – 63 | 103 – 117 | Dangerous situation | High seas over 10 metres |
| 12 | Hurricane | 63 up | 117 up | Dangerous situation | High seas over 14 metres |
