Wind
Wind
If the hourly average wind speed during work hours is at least 30 km/h, or if the peak wind speed is at least 60 km/h, then that hour is deemed bad weather.
If three such hours occur in a row, the rest of the work day is deemed bad weather.
In detail:
A wind speed of 30 km/h corresponds to 5 on the Beaufort scale or 8.3 m/s.