When did windshield washers become standard equipment on automobiles?

Windshield washers didn't become truly *standard* equipment on automobiles at a single, universally agreed-upon time. Their adoption was gradual, varying by manufacturer and market. However, the late 1950s and early 1960s represent a significant period where they transitioned from a relatively uncommon extra to a more common feature. By the mid-1960s, they were becoming much more widespread.