White is fine after Labor Day, providing the fabric and style are appropriate for the weather. White does not look right in Autumn, but is beautiful in winter, especially after a snow.
Wearing white shoes or dresses after Labor Day has been a fashion no no for a long time because white is associated with the beginning of something. Easter time usually marks the beginning of springtime and so the color white is associated with it.
White is a spring/summery color, so wearing white after the official end of summer is technically a fashion no-no. However, you can still wear white shirts, but things like white dresses, skirts or pants are a no-no.
