There is a slew of things made for that all would likely cost more than the weather vane is worth.
https://www.google.ca/search?q=intu...mg&ei=NH7ZXq-qD9Cj-gSt2JSgDA&bih=502&biw=1093
https://www.google.ca/search?q=intu...mg&ei=NH7ZXq-qD9Cj-gSt2JSgDA&bih=502&biw=1093