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 |