ETESLE, or ETESIAN WINDS, are such as blow at stated times of the year, from what point soever of the compass they come. They are so called from the Greek word etes, year, being yearly or anniversary winds, such as are now called monsoons and trade-winds, which in some parts of the world continue constantly blowing in the same direction during stated seasons of the year. Thus the north winds, which during the dog-days constantly blow upon the coasts of Egypt, and prevent all ships sailing out of Alexandria for that season, are called etesie in Caesar's Commentaries; and in other authors, the west and east winds are called etesie when these continue blowing for certain seasons of the year.
Cellarius endeavours to prove that those winds are properly etesian which blow from that part of the horizon which is between the north and west about the time of the solstice. In ancient writers they are represented as of a very mild and gentle kind; and are called somniculosi and delicati, from their sleeping or ceasing to blow in the night.