The Beaufort scale was devised in 1805 by a British Admiral, Sir Francis Beaufort (1774–1857), to help mariners in handling ships. It uses a series of numbers from 0 to 17 to indicate wind speeds and applies to both land and sea.
| Beaufort number |
Name |
Wind speed (mph/kph) |
| 0 |
Calm |
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| 1 |
Light air |
1–3 / 1.5–4.8 |
| 2 |
Light breeze |
4–7 / 6.4–11.3 |
| 3 |
Gentle breeze |
8–12 / 12.9–19.3 |
| 4 |
Moderate breeze |
13–18 / 21–29 |
| 5 |
Fresh breeze |
19–24 / 30.6–38.6 |
| 6 |
Strong breeze |
25–31 / 40.2–50 |
| 7 |
Moderate gale |
32–38 / 51.5–61.1 |
| 8 |
Fresh gale |
39–46 / 62.8–74 |
| 9 |
Strong gale |
47–54 / 75.6–86.9 |
| 10 |
Whole gale |
55–63 / 88.5–101.4 |
| 11 |
Storm |
64–73 / 103–117.5 |
| 12–17 |
Hurricane |
74 /119.1 |
