If you want to learn how to judge wind speeds either; purchase an anemometer or learn the Beaufort scale
"The
Beaufort scale /'bo?f?rt/ is an empirical measure that relates wind speed to observed conditions at sea or on land. Its full name is the
Beaufort wind force scale, although it is a measure of wind speed and not of force in the scientific senses."
See
en.wikipedia.org/wiki/Beaufort_scale for more detail.
Then learn to convert your observations to which ever measure of wind speed turns you on.
