So, it's summer and you are attending approximately 58948594 weddings. A lot of them are outside, which means you're going to look like a chump showing up in that black suit you wear only when you're attending funerals or job interviews (same thing, really).
All you need is a white button down, a pair of khakis, and a snappy tie, like this Coral Seersucker Tie ($98, General Knot Co.) from General Knot Co. You'll look so precious that your grandmother won't be able to stop pinching your cheeks and your Aunt Dorothy will force you into at least four awkward slow dances.
Lucky for you, there's an open bar. Cheers.