As for cuckoo clocks, there are of course some important design principles - the Wikipedia article has some information on this. What I found interesting here is how in the 19th century designing the clocks became a very conscious effort of mixing information with marketable and folkloristic images of the regions of origin, whereas earlier versions seemed to focus more on the mechanical mysteries and the artificiality. In weather vanes, the traditional rooster design adds a religious and mystic dimension (the Biblical reference to Peter’s betrayal, of course, but also the rooster announcing the break of day and the disappearance of bad ghosts), thus linking the informational purpose to the building where it is usually displayed (and thereby sanctioning the curiosity, I’d say).

A similar device is the so-called “weather house” (Wetterhäuschen): This is a traditional form of hygrometer, and in a way a mashup of the informational purposes of a weather stations and the folkloristic feel-good factor of the cuckoo clocks (with a “sun woman” in traditional costume announcing good weather and a “rain man” signifying bad times).