because they have a tradition called SEERSUCKER THURSDAY, which is legit my wet dream.
"in the years before air conditioning made summertime washington bearable, senators from the south shed their heavy-wool black frock coats for lighter linen and cotton garments. seersucker suits became widely popular because they retained their fashionable good looks despite the frequent washing that humid summers made necessary. in the late 1990s, mississippi senator trent lott decided the time had come to revive a long-forgotten senate sartorial tradition. he selected a 'nice and warm' day in the second or third week of june to be designated seersucker thursday."