A classic poem might mention "the warm favonian breezes of spring," indicating that the breezes are from the west — which is where mild or gentle winds were thought to come from in ancient times. Favonian is a literary word.
Favonian comes from Favonius, the name of the west wind in ancient Roman tradition. Because the west wind was regarded so positively, favonian also came to be used metaphorically to mean "favorable" or "benevolent," as in "her favonian smile." The names of the other winds were Boreas, the north wind (from which we get the word boreal, meaning "northern"); Auster, the south wind (the origin of the name Australia); and Eurus, the east wind.