straw in the wind

A minor event or action that predicts or foreshadows a future event. His negative remark about marriage was a straw in the wind that suggested he was headed for a divorce. Bill didn't get the promotion and, looking back, I think his very public argument with the boss was a straw in the wind.

straw(s) in the wind

A clue or test of public opinion or some other matter; fragmentary evidence. This term draws the analogy between blowing straws that indicate the wind’s direction and a test of some other issue. The idea, with slightly different wording, appears in print from the mid-seventeenth century on. “Take a straw and throw it up into the Air, you shall see by that which way the wind is,” wrote John Selden (Table-Talk: Libels, ca. 1654). A related term is straw vote or straw poll, an unofficial tally to show people’s views on an issue or candidate. O. Henry made fun of the idea in A Ruler of Men (1907): “A straw vote only shows which way the hot air blows.”