| Windspeed |
in MPH Description Visible Condition |
| 0 |
Calm Smoke rises vertically |
| 1 - 4 |
Light Air Direction of wind shown by
smoke but not by wind vanes |
| 4 - 7 |
Light Breeze Wind felt on face; leaves
rustle; ordinary wind vane moved by wind |
| 8 - 12 |
Gentle Breeze Leaves and small twigs
in constant motion; wind extends light flag |
| 13 - 18 |
Moderate Breeze Raises dust and loose
paper; small branches are moved |
| 19 - 24 |
Fresh Breeze Small trees in leaf begin
to sway; crested wavelets form on inland water |
| 25 - 31 |
Strong Breeze Large branches in motion;
telephone wires whistle; umbrellas used with difficulty |
| 32 - 38 |
Moderate Gale Whole trees in motion;
inconvenience in walking against wind |
| 39 - 46 |
Fresh Gale Breaks twigs off trees;
generally impedes progress |
| 47 - 54 |
Strong Gale Slight structural damage
occurs; chimney pots and slates removed |
| 55 - 63 |
Whole Gale Trees uprooted; considerable
structural damage occurs |
| 64 - 72 |
Storm Very rarely experienced; accompanied
by widespread damage |
| 73+ |
Hurricane Devastation occurs |
