September is a wonderful month to visit the Hamptons and Montauk! The daily high temperatures range from 75°F to 67°F and daily low temperatures range from 65°F to 57°F. Evenings in Montauk can be cool, so you may want to bring a jacket or shawl!
While there will not be any provided transportation, the cocktail party, reception and after party will all be held at Sole East which is less than a mile from the center of town. If you choose to stay there, you will not need to drive anywhere other than to and from the ceremony which is located in East Hampton, approximately 25 minutes west of Montauk. The Hampton Hopper is a free hop-on, hop off bus service. Check their website for the schedule and frequented stops: www.hamptonhopper.com Uber and Lyft are available throughout the Hamptons.