Artist Yves Klein titled one of his works The Earth Is Blue. Judging from this season’s collections (and his iconic abstract paintings), we’re inclined to believe him. The cool hue is so ubiquitous in nature that it often escapes notice. Yet some of its most vibrant shades—sapphire, turquoise and the artist’s eponymous International Klein Blue—always look unexpected and electric. This season, any blue will do, whether subtle or bold, worn head to toe or as one strong accent. Let the color define your look: Washed-out indigo tones evoke a breezy, bohemian vibe, while saturated shades, like cerulean and lapis lazuli, complement sleek styles. A classic equestrian-themed ensemble starts with Blue Label’s Printed Silk Halter Dress, emblazoned with a Southwestern-inspired pattern and pops of bright turquoise. Channel a beach-bound glamour girl by wearing Black Label’s cobalt Tarian dress, or emulate a world-class athlete in a brilliant ultramarine bomber by RLX. Classic prep staples, such as the cardigan, summer-weight blazer and silk scarf, also get a lift from azure tones. So you can tell Klein that, like the rest of the planet, your wardrobe is blue.