Best time would be spring and autumn, but also in summer not too hot, wetsuit not necessary. Possible to kite at any time. From December to March below 10 C°.
Any Easterly wind will be relatively unobstructed and good. Besides the winter month the direction is usually right. Seldom we have real strong wind here. Anything Westerly will be covered by the island hence is very hard to kite with.
From Shanghai take motorway to Ningbo, stay on the motorway until it ends. Then follow the signs for Zhoushan island until you reach the ferry boat. Use the ferry to get on the island. Then follow the signs Putuo until you cross over the huge straits bridge. Turn right and follow the road until it becomes real small, right before the road becomes small turn sharp left, follow until a t junction and turn right. Now go straight as long as you can and you will find several nice beaches to your left.