Hmmm... I usually go for more citrus based scents in summer, maybe a little green and woodsy too.
Beach Hut Man by Amouage. A clean, green freshness, with mint, ivy, and vetiver, above a woodsy-earthy base of sandalwood and moss. A touch of galbanum, orange blossom, and myrrh add some complexity. Fantastic lasting power, though the initial blast of greenness is pretty wild.
Xerjoff Nio is another fantastic one. More of a citrus-woodsy blend. The bergamot and neroli mixed with spicy pink pepper, nutmeg, cardamom above a warm-woodsy cedar+amber (etc etc) base is brilliant.
Some others, Jardin d'Amalfi by Creed (ludicrously obscene price); both of Neroli Portofino Forte and Mandarino di Amalfi by Tom Ford; Terre d'Hermès Eau Très Fraiche by Hermès (much more reasonable price than any of the others above). Iris Silver Mist by Serge Lutens.