| 0 — Calm | less than 1 mph (0 m/s) |
Smoke rises vertically |
| 1 — Light air | 1 – 3 mph 0.5-1.5 m/s |
Smoke drifts with air, weather vanes inactive |
| 2 — Light breeze | 4 – 7 mph 2-3 m/s |
Weather vanes active, wind felt on face, leaves rustle |
| 3 — Gentle breeze | 8 – 12 mph 3.5-5 m/s |
Leaves & small twigs move, light flags extend |
| 4 — Moderate breeze | 13 – 18 mph 5.5-8 m/s |
Small branches sway, dust & loose paper blows about |
| 5 — Fresh breeze | 19 – 24 mph 8.5-10.5 m/s |
Small trees sway, waves break on inland waters |
| 6 — Strong breeze | 25 – 31 mph 11-13.5 m/s |
Large branches sway, umbrellas difficult to use |
| 7 — Moderate gale | 32 – 38 mph 14-16.5 m/s |
Whole trees sway, difficult to walk against wind |
| 8 — Fresh gale | 39 – 46 mph 17-20 m/s |
Twigs broken off trees, walking against wind very difficult |
| 9 — Strong gale | 47 – 54 mph 20.5-23.5 m/s |
Slight damage to buildings, shingles blown off roof |
| 10 — Whole gale | 55 – 63 mph 24-27.5 m/s |
Trees uprooted, considerable damage to buildings |
| 11 — Storm | 64 – 73 mph 28-31.5 m/s |
Widespread damage, very rare occurrence |
| 12 — Hurricane | over 73 mph over 32 m/s |
Violent destruction |