Source, in full
The Fatal Glass of Beer (1933). Fields adapts an English proverb that was popular in the 17th century. (James Howell, English Proverbs (1659): "When the wind is in the east it is good for neither man nor beast"; John Ray, English Proverbs (1670): "When the wind's in the East, It's neither good for man nor beast." In rhyming "east" with "beast" the proverb refers to weather patterns in the British isles.)