Type of wind | Description | Visible signs |
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 |