Educate Me about Foulards

[J. Cogburn]

As I understand it, a "foulard" refers to a lightweight silk tie which usually - but not always - sports a small printed pattern of some sort.

When is a foulard more desirable to wear than a standard-weight silk tie? I had thought that foulards were primarily worn during the summer (lighter = better when you're hot as hell), but I see in Etutee's AA/Esky articles that foulards were frequently the stylish choice during colder months as well.

So I am confused. Would anyone care to enlighten me regarding the advantages of a foulard relative to a standard-weight silk tie and the best times to wear these puppies? Or is "foulard" often a reference to a small pattern rather than a silk weight?