I don't know how to keep this in a musical vein, but...
Patrick O'Brian, who was known for meticulous research, mentioned in several places that this was a commonly held belief in the Royal Navy in the sail age.
There is also a similar tradition among land-based soldiery of the 19th century (American Civil War in particular). The history seems to give some support to it, oddly enough.
I have wondered before, and will continue to wonder until someone publishes some research, if it has to do with the time it took to move forces into position for a major setpiece battle (naval or land) and the cyclical nature of storms. The idea is that you are tied down by bad weather, you begin to move when conditions clear, and there is - on average - just enough time to maneuver and fight a battle before the next round of bad weather sets in.
Just a thought.
-Glenn