Is it crazy to even consider wearing an outerwear layer in the summertime? Yes and no. When the heat index is soaring, it might feel counterintuitive to throw on a jacket—but the right one can actually be your best warm-weather ally. A lightweight layer helps balance overly air-conditioned interiors, adds structure to breezy summer fits, and gives you that finished look without weighing you down.

This season's summer jackets are all about smart fabric choices and relaxed silhouettes. Think crisp cotton shirt jackets, unlined linen sport coats, airy double-breasted blazers, and chore coats so light they could pass for an overshirt. These aren't your stiff fall layers; they're breathable, tailored without being tight, and designed to move with you. Throw one on over a T-shirt or polo, and suddenly you've gone from “running errands” to “meeting casually for an aperitivo.”

Whether you're dressing for the office, a night out, or just trying to look like a guy who has his act together, a summer jacket is an easy way to level up your look. In short, it's the kind of move that tells people you've thought things through—even if you're still sweating a little. Here are some of our favorite picks to help you layer smarter this season.