North shore is nice to stay, but no wind in the summer. Wind is on the SE coast and S coast for wind and summer swells. You will be relying mainly on the trade winds that time of year and those are the hottest two months. Around Kapaa on the east shore is wind and Poipu on the south shore. Call or email one of the local shops there for more clarity.
By the way, you should check out GK Kites and Lightwave boards. I just got a quiver and boards and the kites are rugged and boards are state of the art. www.globekites.com