As it was explained to me in an earlier post, the LED colour is activated by the wind velocity. I see it from my balcony. Blue means no wind while red means it's quite gusty and I think yellow might mean head for the root cellar (and be quick about it!).I was just down there today (stupid me) took be 1:30min to get home.
I love the LED/light house (that's what it resembles) on the top of this thing, it changes colour every 1/2 seconds, yellow/blue/red ... it's quite bright too, I'll take pictures next time.