Wind barbs show the direction from where the wind is originating. The strength is visualized in 5 knot increments and always rounded to the next higher value. As there are no colors in lockscreen widgets, wind strength is always displayed including gusts.
Winds higher than 99 knots will not be displayed properly.
Find more information about wind barbs on Wikipedia.
Note:
Temperature, visibility, and wind are reported in the units defined by the user.