Three styles spring to mind on the subject of what to wear at a summer wedding. I base most of my decision on the time of day and the formality of the event. Also, are you invited to the reception as well as the ceremony?
Above are three choices based on all those considerations. Look A is a simple wrap dress and wedges, a great all purpose look that can be dressed up or down. Look B is a more upscale and fun look for an afternoon affair or garden ceremony. And finally, Look C is the formal evening, va-va-voom!, party all night long, look.