Not sure if this would interest all. I downloaded a Android App onto my smart phone called Zephyrus windmeter. It uses the phones microphone to take wind speed readings. It reads in M/s but with a conversion app you can easily covert to mph or kph.
The free version also does a average speed reading and max speed. Not sure how accurate it is but a good tool when assessing conditions. Just need a app to make screen visible in bright sunlight.

huh, pretty cool. I'll try it next time I go out. Seemed to react appropriately to me blowing into the mic lol

EDIT: looking at the conversion, going from m/s to knots appears to be 1.95, so a quick conversion is to double the m/s reading to get knots.