Here’s a good graphic of the Beaufort Scale.
It’s easy to see that at as the wind speed increase the ranges increase. F-1 is a narrower range than F-11. This is because at low wind speeds it’s easier to detect slight differences in wind speed than a higher speeds. For example the visual difference between 2 kts and 5 kts can be easily seen compared to say 26 kts and 29 kts.
