Charleston is known for its unique culture, which blends traditional Southern U.S., English, French, and West African elements. The downtown peninsula has gained a reputation for its art, music, local cuisine, and fashion. Spoleto Festival USA, held annually in late spring, has become one of the world's major performing arts festivals. It was founded in 1977 by Pulitzer Prize-winning composer Gian Carlo Menotti, who sought to establish a counterpart to the Festival dei Due Mondi (the Festival of Two Worlds) in Spoleto, Italy.

Answer this question, if possible (if impossible, reply "unanswerable"): What season isn't Spoleto Festival USA held?
unanswerable