Advertising that only shows when it rains

This is an interesting use of media, the paint used to create this tires advert, I guess suggesting that the company work well in the rain, driving message, only appears when it rains

I suppose this might make people notice it if they go that way often enough to notice that it appears and disappears,

http://www.designboom.com/weblog/cat/8/view/8644/raincampaign-continental-tires.html