There are few places where you can get within an hour and a half by public transportation from Manhattan. For south, east winds: Plumb Beach
For North/West: Seagate, Cross Bay blvd, or Breezy Point
1-2 windy days in the summer per week and 3-4 windy days in the spring/fall per week.
summer time: 12 - 17 m kties | shorty
spring, fall 10 - 12m kites | 5/4 mm wetsuit
winter 8-12m kites | 6/5 mm wetsuit or drysuit
For the community checkout kitehood http://kitehood.com/community
. Locals are friendly, just introduce yourself when you get on the beach.