Labor Day used to be considered the last day of summer as well as the end of the summer white or seersucker clothing season. That latter custom has departed, as has much of the day's end of season connotations. Children no longer return to school at the start of September and men can wear their summer clothing for as long as the weather permits. Even Emily Post's Etiquette, a relatively conservative auuthority, gives the OK in its 17th edition.
Most seersucker is blue or gray of course, but André Churchwell's is pink. And he will continue wearing it.