I've got the Sparkfun wind and rain guage sensors. The wind part seemed to be fine, but all the time I've had issues with false readings from the rain guage. I've determined it doesn't seem to be moving, but it may be that wind occasionally makes the bucket tip falsely.
In the thread from Sparkfun's listing of the item I found this circuit: http://spassbremse.de/wordpress/wp-content/uploads/2012/04/windfahne_Schaltplan.png
which adds an RC circuit for low pass filtering. Since adding this in the way shown, I now get no readings at all from either instrument the wind speed or rain guage instruments. I did however discover that I got false readings when switching my soldering iron on or off.
Since then I've added a .22mF capacitor between the power and ground rail, but still got one false trigger on the rain guage when switching my iron on or off. Any suggestions for making this thing workable? I'm running it in a USB powered way. Thanks,