| Nome |
Symbol |
m/s |
Km/h |
Knot |
Characteristics |
| 0 |
Calm |
 |
< 0.3 |
< 1 |
< 1 |
Calm. Smoke rises vertically. |
| 1 |
Light air |
 |
0.3 – 1.5 |
1 – 5 |
1 – 2 |
Wind motion visible in smoke |
| 2 |
Light breeze |
 |
1.5 – 3.3 |
6 – 11 |
3 – 6 |
Wind felt on exposed skin. Leaves rustle. |
| 3 |
Gentle breeze |
 |
3.3 – 5.5 |
12 – 19 |
7 – 10 |
Leaves and smaller twigs in constant motion. |
| 4 |
Moderate breeze |
 |
5.5 – 8.0 |
20 – 28 |
11 – 15 |
Dust and loose paper raised. Small branches begin to move. |
| 5 |
Fresh breeze |
 |
8.0 – 11 |
29 – 38 |
16 – 20 |
Branches of a moderate size move. Small trees begin to sway. |
| 6 |
Strong breeze |
 |
11 – 14 |
39 – 49 |
21 – 26 |
Large branches in motion. Whistling heard in overhead wires. Umbrella use becomes difficult. Empty plastic garbage cans tip over. |
| 7 |
High wind, Moderate gale, Near gale |
 |
14 – 17 |
50 – 61 |
27 – 33 |
Whole trees in motion. Effort needed to walk against the wind. Swaying of skyscrapers may be felt, especially by people on upper floors. |
| 8 |
Gale, Fresh gale |
 |
17 – 20 |
62 – 74 |
34 – 40 |
Some twigs broken from trees. Cars veer on road. Progress on foot is seriously impeded. |
| 9 |
Strong gale |
 |
21 – 24 |
75 – 88 |
41 – 47 |
Some branches break off trees, and some small trees blow over. Construction/temporary signs and barricades blow over. Damage to circus tents and canopies. |
| 10 |
Storm, Whole gale |
 |
25 – 28 |
89 – 102 |
48 – 55 |
Trees are broken off or uprooted, saplings bent and deformed. Poorly attached asphalt shingles and shingles in poor condition peel off roofs. |
| 11 |
Violent storm |
 |
29 – 32 |
103 – 117 |
56 – 63 |
Widespread vegetation damage. Many roofing surfaces are damaged; asphalt tiles that have curled up and/or fractured due to age may break away completely. |
| 12 |
Hurricane |
 |
≥ 33 |
≥ 118 |
≥ 64 |
Very widespread damage to vegetation. Some windows may break; mobile homes and poorly constructed sheds and barns are damaged. Debris may be hurled about. |
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