The Beaufort scale is an empirical way of describing wind force from 0 to 12. It began with wind effects on sailing ships and was later standardised using speed ranges and sea state.
Beaufort force is a category, not a separate physical unit. A small speed change near a boundary can change the integer force without a dramatic real-world change.
Mean wind and gusts
Beaufort tables usually refer to mean wind speed at a standard height. A short gust can be substantially stronger than the mean.
For bridges, sailing, mountain routes and fire weather, gusts and direction often matter more than a single Beaufort number.
Sea state and fetch
Beaufort sea descriptions assume enough distance and time for waves to develop. Inside a sheltered bay or near a lee shore, conditions may be milder.
Conversely, existing swell may keep waves significant after local wind has eased.
Proper use
Read Beaufort together with km/h or knots, gusts, direction, wave height and period. For marine activity, follow official forecasts and local port guidance.
The e‑meteo calculator uses standard speed ranges and cannot predict local acceleration.
These explanations and calculations are educational. For safety, occupational, health, marine or aviation decisions, follow the appropriate official services.