| 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 |