Proenza Schouler acetate sunglasses, $290, at Ilori, 138 Spring St., nr. Wooster St.; 212-226-8276.   (Photo: Hannah Whitaker)

Every summer has its wardrobe: a few pieces that catch on and suddenly define the season (gladiator sandals, anybody?). We’ve sifted through the trends and determined what we’ll all be seeing, in some form, for the next four months.

Round Sunglasses

(Photo: Hannah Whitaker)

Purple Label sunglasses, $375
at Ralph Lauren Eyewear
811 Madison Ave., at 68th St.; 212-988-4620

(Photo: Hannah Whitaker)

Linda Farrow Luxe sunglasses, $440
at Aloha Rag
505 Greenwich St., at Spring St.; 212-925-0882.

(Photo: Hannah Whitaker)

Encircie sunglasses, $10
at Urban Outfitters
526 Sixth Ave., at 14th St.; 646-638-1646.