No idea what this is called, but I know it is part of Gordon's Weather Station and this somehow sends info about the wind to the device inside the house - very clever. The reason I noticed it today was because I have been hanging washing outside and it is on the fence close by.
Or at least it was this morning. Now it has moved to another fence. Apparently a neighbour is doing a bit of reconstruction of a summer house on the other side of the fence and was worried he might damage the wind thing. So Gordon was quite happy to move it out of the way.
The Extra shows the screen at the same time as I took the photo - it was an easterly breeze which just about got the washing dry, but it was cold - wind chill.