What's the real reason behind the raised eyebrows regarding white after Labor Day. It's a tough cookie to crack.
Originally, the rule was more a long the lines of "Only wear white shoes between Memorial Day and Labor Day." Furthermore, it mainly applied to white pumps or dress shoes. White tennis shoes and off-white boots seem exempt, as are any shoes worn by a winter bride. "Winter white" clothing (e.g., cream-colored wool) is acceptable between Labor Day and Memorial Day too.
The only logical reasoning I could find cited temperature; suggesting that because white reflects light and heat, wearing white would make you cooler in winter, and thus should be avoided. Some gurus suggest the rule stems from a class issue stating that in the late 19th century and the 1950s, more people were entering the middle classes. These nouveau-riche folks were unaware of the standards of high society, so they were given specific codified rules to follow in order to fit in, one of the rules being, no white after Labor Day.
Location is key too. According to my reading, it's often wondered if fashion in the American South can be a little more formal than elsewhere, perhaps the no-white-shoes rule came from south of the Mason-Dixon Line?
Whatever. Marilyn Monroe rocked white all the time! Happy Happy Labor Day!!!