I have always been a bit of an Astronomy nerd and thought that a great theme for a summer wedding would be a Star Party. Even better if you can plan your wedding during a Meteor Shower! (the Perseids Meteor Shower is usually most visible during the second week of August, just saying…)
Plan the ceremony for the late afternoon or early evening and then party on into the night! Set up a nice tent for the reception, some place rural with great open views of the sky. Decorations would be simple, charming, rustic, possibly homemade if you are feeling up to a DiY project! Light your tent with some string lights and swags of tulle or sheer fabrics, accent with paper lanterns or mason jar lights!
I envision a vintage inspired gown, but with some modern flare (Check out BHLDN, they fit this aesthetic perfectly). Dress your bridesmaids in something simple but with a little sparkle to invoke the theme.