And, more importantly, why it no longer applies.

For a lot of women, Labor Day isn't only about saying goodbye to summer, but an entire section of our wardrobes.

For generations, we've subscribed to the old adage that wearing white after Labor Day is a fashion faux pas up there with wearing socks with sandals.  But why? And more importantly, does it still apply?

There are a few theories about the origin of this strange rule. A Time article from 2009 suggests that it might have been born out of function. Before the days of air conditioning, white attire was cooler to wear in the dog days of summer because it reflects the sun.

And then there's the idea that it arose out of pure snobbery. In the early 20th century, Americans who set the fashion trends were the same ones who could afford to depart the cities for the summer months. Safe in the county, far away from the urban grime, they wore white simply because they could. Keep in mind that nobody in their right mind wore white in the city back then—it was far too dirty. "If you look at any photograph of any city in America in the 1930s, you'll see people in dark clothes," Charlie Scheips, author of American Fashion told Time. White clothes, on the other hand, were "a look of leisure."

Labor Day traditionally marks the end of the summer, which, for the well-heeled, meant returning to the city and forgoing their white country clothes.

By the 1950s, this thinking had trickled down to the middle class, and with help from women's magazines, it was accepted that white wasn't appropriate past Labor Day. But that's not to say that everyone agreed. Coco Chanel, for example, famously wore white year-round.

Fortunately, fashion rules have become considerably more relaxed, and these days, tastemakers agree that you should wear white every day of the year if you want to.

So, there you have it. Consider the ban on white after Labor Day officially ended!