not necessarily a "summer fragrance" but the new Chanel Tendre is light and smells WONDERFUL! I can't get enough of it! Its nordies exclusive right now
For summertime I like Philosophy's Pure Grace or Baby Grace... It gets to be about 150,000 degrees here in the summer (AZ) and I can't stand anything heavy.
For clean "shower-fresh," Banana Republic W is wonderful.
For clean citrus or tea, try Elizabeth Arden Green Tea, Bulgari Eau The Verta (I didn't get the name quite right, but it's something similar), or the new Serge Lutens L'Eau.
For a beach-y smelling fragrance, Robert Piguet Fracas, Frederic Malle Carnal Flower, Bond New York Fire Island, Bobbi Brown Beach, Estee Lauder Bronze Goddess.