In the years before air conditioning made summertime Washington bearable, senators from the South had much to teach their colleagues from other regions about proper attire. As spring merged into summer, southern senators shed their heavy-wool black frock coats for lighter linen and cotton garments. In 1907, a New Orleans clothier made summer wear more comfortable by designing a light-weight suit in pale blue and white striped rumpled cotton fabric. He named that fabric “seersucker,” from Persian words meaning “milk and sugar.” Seersucker suits became widely popular because they retained their fashionable good looks despite the frequent washing that humid summers made necessary.
Senatorial garb, from men’s Victorian swallowtail coats to women’s modern-era pantsuits, has regularly attracted media attention. Well into the 20th century, on the first warm days of spring, journalists routinely filed stories on the seasonal transformation evident in the poorly ventilated Senate Chamber. By the 1950s, however, modern air-conditioning had finally reached the capital city’s interior spaces, making for year-round comfort—and year-round congressional sessions.
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. His goal was to show that “the Senate isn’t just a bunch of dour folks wearing dark suits and—in the case of men—red or blue ties.” On the day before each year’s event, senators are alerted to the impending “wearing of the seersucker.” In 2004, California Senator Dianne Feinstein decided to encourage participation by the growing cadre of the Senate’s women members. “I would watch the men preening in the Senate,” she said, “and I figured we should give them a little bit of a horse race.” The following year, 11 of the 14 women senators appeared on Seersucker Thursday in outfits received as gifts from Senator Feinstein. Today, senators voluntarily make this annual fashion statement in a spirit of good-humored harmony to remind their colleagues of what earlier Senates considered mandatory summer attire.
From The New Members' Guide to Traditions of the United States Senate, by Richard A. Baker (S. Pub. 109-25).